Android: Factor out favicon-related stuff out of Tab

TabFavicon is Tab userdata that provides API for the active
web contents' favicon. This was a part of Tab class but
factored out into its own class.

Bug: 877878, 925242
Change-Id: I49eba08918a2a86985f2b8aea5d4c7e15d666108
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1482434
Commit-Queue: Jinsuk Kim <jinsukkim@chromium.org>
Reviewed-by: David Trainor <dtrainor@chromium.org>
Reviewed-by: Theresa <twellington@chromium.org>
Cr-Commit-Position: refs/heads/master@{#637993}

chrome/android/BUILD.gn

@@ -2346,6 +2346,7 @@ generate_jni("jni_headers") {
     "java/src/org/chromium/chrome/browser/suggestions/SuggestionsEventReporterBridge.java",
     "java/src/org/chromium/chrome/browser/sync/ProfileSyncService.java",
     "java/src/org/chromium/chrome/browser/tab/Tab.java",
+    "java/src/org/chromium/chrome/browser/tab/TabFavicon.java",
     "java/src/org/chromium/chrome/browser/tab/TabState.java",
     "java/src/org/chromium/chrome/browser/tab/TabWebContentsDelegateAndroid.java",
     "java/src/org/chromium/chrome/browser/tabmodel/SingleTabModel.java",

chrome/android/java/src/org/chromium/chrome/browser/compositor/LayerTitleCache.java

@@ -20,6 +20,7 @@ import org.chromium.chrome.browser.favicon.FaviconHelper.DefaultFaviconHelper;
 import org.chromium.chrome.browser.favicon.FaviconHelper.FaviconImageCallback;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tab.TabFavicon;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
 import org.chromium.ui.base.DeviceFormFactor;
 import org.chromium.ui.resources.ResourceManager;
@@ -125,7 +126,7 @@ public class LayerTitleCache implements TitleCache {
         boolean isHTSEnabled = !DeviceFormFactor.isNonMultiDisplayContextOnTablet(tab.getActivity())
                 && ChromeFeatureList.isEnabled(ChromeFeatureList.HORIZONTAL_TAB_SWITCHER_ANDROID);
         boolean isDarkTheme = tab.isIncognito() && !isHTSEnabled;
-        Bitmap originalFavicon = tab.getFavicon();
+        Bitmap originalFavicon = TabFavicon.getBitmap(tab);
         if (originalFavicon == null) {
             originalFavicon = mDefaultFaviconHelper.getDefaultFaviconBitmap(
                     mContext, tab.getUrl(), !isDarkTheme);

chrome/android/java/src/org/chromium/chrome/browser/tab/Tab.java

@@ -9,8 +9,6 @@ import android.app.Activity;
 import android.content.Context;
 import android.content.Intent;
 import android.content.res.Configuration;
-import android.content.res.Resources;
-import android.graphics.Bitmap;
 import android.graphics.Color;
 import android.graphics.Rect;
 import android.net.Uri;
@@ -185,17 +183,6 @@ public class Tab
     private boolean mIsClosing;
     private boolean mIsShowingErrorPage;
 
-    private Bitmap mFavicon;
-    private int mFaviconWidth;
-    private int mFaviconHeight;
-    private String mFaviconUrl;
-
-    /**
-     * The size in pixels at which favicons will be drawn. Ideally mFavicon will have this size to
-     * avoid scaling artifacts.
-     */
-    private int mIdealFaviconSize;
-
     /** Whether or not the TabState has changed. */
     private boolean mIsTabStateDirty = true;
 
@@ -396,9 +383,6 @@ public class Tab
         mLaunchType = type;
         mLaunchTypeAtCreation = type;
 
-        Resources resources = mThemedApplicationContext.getResources();
-        mIdealFaviconSize = resources.getDimensionPixelSize(R.dimen.default_favicon_size);
-
         TabThemeColorHelper.createForTab(this);
 
         // Restore data from the TabState, if it existed.
@@ -1421,6 +1405,7 @@ public class Tab
             updateInteractableState();
             mWebContentsDelegate = mDelegateFactory.createWebContentsDelegate(this);
             TabWebContentsObserver.from(this);
+            TabFavicon.from(this);
 
             int parentId = getParentId();
             if (parentId != INVALID_TAB_ID) {
@@ -1663,22 +1648,6 @@ public class Tab
         return mIsTitleDirectionRtl;
     }
 
-    /**
-     * @return The bitmap of the favicon scaled to 16x16dp. null if no favicon
-     *         is specified or it requires the default favicon.
-     */
-    public Bitmap getFavicon() {
-        // If we have no content or a native page, return null.
-        if (isNativePage() || getWebContents() == null) return null;
-
-        // Use the cached favicon only if the page wasn't changed.
-        if (mFavicon != null && mFaviconUrl != null && mFaviconUrl.equals(getUrl())) {
-            return mFavicon;
-        }
-
-        return nativeGetFavicon(mNativeTabAndroid);
-    }
-
     /**
      * Loads the tab if it's not loaded (e.g. because it was killed in background).
      * This will trigger a regular load for tabs with pending lazy first load (tabs opened in
@@ -1904,49 +1873,6 @@ public class Tab
         return mWebContentsDelegate;
     }
 
-    private boolean isIdealFaviconSize(int width, int height) {
-        return width == mIdealFaviconSize && height == mIdealFaviconSize;
-    }
-
-    /**
-     * @param width new favicon's width.
-     * @param height new favicon's height.
-     * @return true iff the new favicon should replace the current one.
-     */
-    private boolean isBetterFavicon(int width, int height) {
-        if (isIdealFaviconSize(width, height)) return true;
-
-        // Prefer square favicons over rectangular ones
-        if (mFaviconWidth != mFaviconHeight && width == height) return true;
-        if (mFaviconWidth == mFaviconHeight && width != height) return false;
-
-        // Do not update favicon if it's already at least as big as the ideal size in both dimens
-        if (mFaviconWidth >= mIdealFaviconSize && mFaviconHeight >= mIdealFaviconSize) return false;
-
-        // Update favicon if the new one is larger in one dimen, but not smaller in the other
-        return (width > mFaviconWidth && !(height < mFaviconHeight))
-                || (!(width < mFaviconWidth) && height > mFaviconHeight);
-    }
-
-    @CalledByNative
-    protected void onFaviconAvailable(Bitmap icon) {
-        if (icon == null) return;
-        String url = getUrl();
-        boolean pageUrlChanged = !url.equals(mFaviconUrl);
-        // This method will be called multiple times if the page has more than one favicon.
-        // We are trying to use the |mIdealFaviconSize|x|mIdealFaviconSize| DP icon here, or the
-        // first one larger than that received. Bitmap.createScaledBitmap will return the original
-        // bitmap if it is already |mIdealFaviconSize|x|mIdealFaviconSize| DP.
-        if (pageUrlChanged || isBetterFavicon(icon.getWidth(), icon.getHeight())) {
-            mFavicon = Bitmap.createScaledBitmap(icon, mIdealFaviconSize, mIdealFaviconSize, true);
-            mFaviconWidth = icon.getWidth();
-            mFaviconHeight = icon.getHeight();
-            mFaviconUrl = url;
-        }
-
-        for (TabObserver observer : mObservers) observer.onFaviconUpdated(this, icon);
-    }
-
     /**
      * Checks if this tab is currently presented in the context of custom tabs. Tabs can be moved
      * between different activities so the returned value might change over the lifetime of the tab.
@@ -2626,7 +2552,6 @@ public class Tab
             long intentReceivedTimestamp);
     private native void nativeSetActiveNavigationEntryTitleForUrl(long nativeTabAndroid, String url,
             String title);
-    private native Bitmap nativeGetFavicon(long nativeTabAndroid);
     private native void nativeCreateHistoricalTab(long nativeTabAndroid);
     private native void nativeUpdateBrowserControlsState(
             long nativeTabAndroid, int constraints, int current, boolean animate);

chrome/android/java/src/org/chromium/chrome/browser/tab/TabFavicon.java

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.chrome.browser.tab;
+
+import android.content.res.Resources;
+import android.graphics.Bitmap;
+
+import org.chromium.base.ObserverList.RewindableIterator;
+import org.chromium.base.annotations.CalledByNative;
+import org.chromium.chrome.R;
+import org.chromium.content_public.browser.WebContents;
+
+/**
+ * Fetches a favicon for active WebContents in a Tab.
+ */
+public class TabFavicon extends TabWebContentsUserData {
+    private static final Class<TabFavicon> USER_DATA_KEY = TabFavicon.class;
+
+    private final Tab mTab;
+    private final long mNativeTabFavicon;
+
+    /**
+     * The size in pixels at which favicons will be drawn. Ideally mFavicon will have this size to
+     * avoid scaling artifacts.
+     */
+    private final int mIdealFaviconSize;
+
+    private Bitmap mFavicon;
+    private int mFaviconWidth;
+    private int mFaviconHeight;
+    private String mFaviconUrl;
+
+    static TabFavicon from(Tab tab) {
+        TabFavicon favicon = get(tab);
+        if (favicon == null) {
+            favicon = tab.getUserDataHost().setUserData(USER_DATA_KEY, new TabFavicon(tab));
+        }
+        return favicon;
+    }
+
+    private static TabFavicon get(Tab tab) {
+        return tab.getUserDataHost().getUserData(USER_DATA_KEY);
+    }
+
+    /**
+     * @param tab Tab containing the web contents's favicon.
+     * @return {@link Bitmap} of the favicon.
+     */
+    public static Bitmap getBitmap(Tab tab) {
+        TabFavicon tabFavicon = get(tab);
+        return tabFavicon != null ? tabFavicon.getFavicon() : null;
+    }
+
+    private TabFavicon(Tab tab) {
+        super(tab);
+        Resources resources = tab.getThemedApplicationContext().getResources();
+        mIdealFaviconSize = resources.getDimensionPixelSize(R.dimen.default_favicon_size);
+        mTab = tab;
+        mNativeTabFavicon = nativeInit();
+    }
+
+    @Override
+    public void initWebContents(WebContents webContents) {
+        nativeSetWebContents(mNativeTabFavicon, webContents);
+    }
+
+    @Override
+    public void cleanupWebContents(WebContents webContents) {
+        nativeResetWebContents(mNativeTabFavicon);
+    }
+
+    @Override
+    public void destroyInternal() {
+        nativeOnDestroyed(mNativeTabFavicon);
+    }
+
+    /**
+     * @return The bitmap of the favicon scaled to 16x16dp. null if no favicon
+     *         is specified or it requires the default favicon.
+     */
+    private Bitmap getFavicon() {
+        // If we have no content or a native page, return null.
+        if (mTab.isNativePage() || mTab.getWebContents() == null) return null;
+
+        // Use the cached favicon only if the page wasn't changed.
+        if (mFavicon != null && mFaviconUrl != null && mFaviconUrl.equals(mTab.getUrl())) {
+            return mFavicon;
+        }
+
+        return nativeGetFavicon(mNativeTabFavicon);
+    }
+
+    /**
+     * @param width new favicon's width.
+     * @param height new favicon's height.
+     * @return true iff the new favicon should replace the current one.
+     */
+    private boolean isBetterFavicon(int width, int height) {
+        if (isIdealFaviconSize(width, height)) return true;
+
+        // Prefer square favicons over rectangular ones
+        if (mFaviconWidth != mFaviconHeight && width == height) return true;
+        if (mFaviconWidth == mFaviconHeight && width != height) return false;
+
+        // Do not update favicon if it's already at least as big as the ideal size in both dimens
+        if (mFaviconWidth >= mIdealFaviconSize && mFaviconHeight >= mIdealFaviconSize) return false;
+
+        // Update favicon if the new one is larger in one dimen, but not smaller in the other
+        return (width > mFaviconWidth && !(height < mFaviconHeight))
+                || (!(width < mFaviconWidth) && height > mFaviconHeight);
+    }
+
+    private boolean isIdealFaviconSize(int width, int height) {
+        return width == mIdealFaviconSize && height == mIdealFaviconSize;
+    }
+
+    @CalledByNative
+    private void onFaviconAvailable(Bitmap icon) {
+        if (icon == null) return;
+        String url = mTab.getUrl();
+        boolean pageUrlChanged = !url.equals(mFaviconUrl);
+        // This method will be called multiple times if the page has more than one favicon.
+        // We are trying to use the |mIdealFaviconSize|x|mIdealFaviconSize| DP icon here, or the
+        // first one larger than that received. Bitmap.createScaledBitmap will return the original
+        // bitmap if it is already |mIdealFaviconSize|x|mIdealFaviconSize| DP.
+        if (pageUrlChanged || isBetterFavicon(icon.getWidth(), icon.getHeight())) {
+            mFavicon = Bitmap.createScaledBitmap(icon, mIdealFaviconSize, mIdealFaviconSize, true);
+            mFaviconWidth = icon.getWidth();
+            mFaviconHeight = icon.getHeight();
+            mFaviconUrl = url;
+        }
+
+        RewindableIterator<TabObserver> observers = mTab.getTabObservers();
+        while (observers.hasNext()) observers.next().onFaviconUpdated(mTab, icon);
+    }
+
+    private native long nativeInit();
+    private native void nativeOnDestroyed(long nativeTabFavicon);
+    private native void nativeSetWebContents(long nativeTabFavicon, WebContents webContents);
+    private native void nativeResetWebContents(long nativeTabFavicon);
+    private native Bitmap nativeGetFavicon(long nativeTabFavicon);
+}

chrome/android/java/src/org/chromium/chrome/browser/tasks/tab_list_ui/TabListMediator.java

@@ -16,6 +16,7 @@ import org.chromium.chrome.browser.favicon.FaviconHelper;
 import org.chromium.chrome.browser.profiles.Profile;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tab.TabFavicon;
 import org.chromium.chrome.browser.tab.TabObserver;
 import org.chromium.chrome.browser.tabmodel.TabModel;
 import org.chromium.chrome.browser.tabmodel.TabModelSelector;
@@ -202,7 +203,7 @@ class TabListMediator {
                 new PropertyModel.Builder(TabProperties.ALL_KEYS_TAB_GRID)
                         .with(TabProperties.TAB_ID, tab.getId())
                         .with(TabProperties.TITLE, tab.getTitle())
-                        .with(TabProperties.FAVICON, tab.getFavicon())
+                        .with(TabProperties.FAVICON, TabFavicon.getBitmap(tab))
                         .with(TabProperties.IS_SELECTED, isSelected)
                         .with(TabProperties.TAB_SELECTED_LISTENER, mTabSelectedListener)
                         .with(TabProperties.TAB_CLOSED_LISTENER, mTabClosedListener)

chrome/android/java/src/org/chromium/chrome/browser/widget/accessibility/AccessibilityTabModelListItem.java

@@ -35,6 +35,7 @@ import org.chromium.base.annotations.UsedByReflection;
 import org.chromium.chrome.R;
 import org.chromium.chrome.browser.tab.EmptyTabObserver;
 import org.chromium.chrome.browser.tab.Tab;
+import org.chromium.chrome.browser.tab.TabFavicon;
 import org.chromium.chrome.browser.tab.TabObserver;
 import org.chromium.chrome.browser.util.ColorUtils;
 
@@ -333,7 +334,7 @@ public class AccessibilityTabModelListItem extends FrameLayout implements OnClic
 
     private void updateFavicon() {
         if (mTab != null) {
-            Bitmap bitmap = mTab.getFavicon();
+            Bitmap bitmap = TabFavicon.getBitmap(mTab);
             if (bitmap != null) {
                 // Don't tint favicon bitmaps.
                 ApiCompatibilityUtils.setImageTintList(mFaviconView, null);

chrome/android/java_sources.gni

@@ -1527,6 +1527,7 @@ chrome_java_sources = [
   "java/src/org/chromium/chrome/browser/tab/TabContextMenuItemDelegate.java",
   "java/src/org/chromium/chrome/browser/tab/TabContextMenuPopulator.java",
   "java/src/org/chromium/chrome/browser/tab/TabDelegateFactory.java",
+  "java/src/org/chromium/chrome/browser/tab/TabFavicon.java",
   "java/src/org/chromium/chrome/browser/tab/TabFullscreenHandler.java",
   "java/src/org/chromium/chrome/browser/tab/TabGestureStateListener.java",
   "java/src/org/chromium/chrome/browser/tab/TabIdManager.java",

chrome/android/junit/src/org/chromium/chrome/browser/tasks/tab_list_ui/GridTabSwitcherMediatorUnitTest.java

@@ -20,7 +20,6 @@ import static org.chromium.chrome.browser.tasks.tab_list_ui.GridTabSwitcherMedia
 
 import android.content.Context;
 import android.content.res.Resources;
-import android.graphics.Bitmap;
 import android.view.View;
 
 import org.junit.After;
@@ -356,7 +355,6 @@ public class GridTabSwitcherMediatorUnitTest {
         doReturn(id).when(tab).getId();
         doReturn("").when(tab).getUrl();
         doReturn(title).when(tab).getTitle();
-        doReturn(Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888)).when(tab).getFavicon();
         doReturn(false).when(tab).isClosing();
         return tab;
     }

chrome/android/junit/src/org/chromium/chrome/browser/tasks/tab_list_ui/TabListMediatorUnitTest.java

@@ -287,7 +287,6 @@ public class TabListMediatorUnitTest {
         doReturn(id).when(tab).getId();
         doReturn("").when(tab).getUrl();
         doReturn(title).when(tab).getTitle();
-        doReturn(Bitmap.createBitmap(1, 1, Bitmap.Config.ARGB_8888)).when(tab).getFavicon();
         return tab;
     }
 }

chrome/browser/BUILD.gn

@@ -2506,6 +2506,8 @@ jumbo_split_static_library("browser") {
       "android/subresource_filter/test_subresource_filter_publisher.cc",
       "android/tab_android.cc",
       "android/tab_android.h",
+      "android/tab_favicon.cc",
+      "android/tab_favicon.h",
       "android/tab_printer.cc",
       "android/tab_printer.h",
       "android/tab_state.cc",

chrome/browser/android/tab_android.cc

@@ -50,7 +50,6 @@
 #include "components/bookmarks/browser/bookmark_utils.h"
 #include "components/bookmarks/managed/managed_bookmark_service.h"
 #include "components/dom_distiller/core/url_utils.h"
-#include "components/favicon/content/content_favicon_driver.h"
 #include "components/navigation_interception/intercept_navigation_delegate.h"
 #include "components/navigation_interception/navigation_params.h"
 #include "components/sessions/content/content_live_tab.h"
@@ -71,17 +70,11 @@
 #include "jni/Tab_jni.h"
 #include "net/base/escape.h"
 #include "services/service_manager/public/cpp/interface_provider.h"
-#include "skia/ext/image_operations.h"
 #include "third_party/blink/public/common/associated_interfaces/associated_interface_provider.h"
 #include "ui/android/view_android.h"
 #include "ui/android/window_android.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/base/window_open_disposition.h"
-#include "ui/display/display.h"
-#include "ui/display/screen.h"
-#include "ui/gfx/android/java_bitmap.h"
-#include "ui/gfx/favicon_size.h"
-#include "ui/gfx/image/image_skia.h"
 
 using base::android::AttachCurrentThread;
 using base::android::ConvertUTF8ToJavaString;
@@ -310,25 +303,6 @@ bool TabAndroid::HasPrerenderedUrl(GURL gurl) {
   return false;
 }
 
-void TabAndroid::OnFaviconUpdated(favicon::FaviconDriver* favicon_driver,
-                                  NotificationIconType notification_icon_type,
-                                  const GURL& icon_url,
-                                  bool icon_url_changed,
-                                  const gfx::Image& image) {
-  if (notification_icon_type != NON_TOUCH_LARGEST &&
-      notification_icon_type != TOUCH_LARGEST) {
-    return;
-  }
-
-  SkBitmap favicon = image.AsImageSkia().GetRepresentation(1.0f).GetBitmap();
-  if (favicon.empty())
-    return;
-
-  JNIEnv* env = base::android::AttachCurrentThread();
-  Java_Tab_onFaviconAvailable(env, weak_java_tab_.get(env),
-                              gfx::ConvertToJavaBitmap(&favicon));
-}
-
 bool TabAndroid::IsCurrentlyACustomTab() {
   JNIEnv* env = base::android::AttachCurrentThread();
   return Java_Tab_isCurrentlyACustomTab(env, weak_java_tab_.get(env));
@@ -366,12 +340,6 @@ void TabAndroid::InitWebContents(
   web_contents_delegate_->LoadProgressChanged(web_contents(), 0);
   web_contents()->SetDelegate(web_contents_delegate_.get());
 
-  favicon::FaviconDriver* favicon_driver =
-      favicon::ContentFaviconDriver::FromWebContents(web_contents_.get());
-
-  if (favicon_driver)
-    favicon_driver->AddObserver(this);
-
   synced_tab_delegate_->SetWebContents(web_contents(), jparent_tab_id);
 
   // Verify that the WebContents this tab represents matches the expected
@@ -411,12 +379,6 @@ void TabAndroid::DestroyWebContents(JNIEnv* env,
 
   WebContentsObserver::Observe(nullptr);
 
-  favicon::FaviconDriver* favicon_driver =
-      favicon::ContentFaviconDriver::FromWebContents(web_contents_.get());
-
-  if (favicon_driver)
-    favicon_driver->RemoveObserver(this);
-
   web_contents()->SetDelegate(nullptr);
 
   if (delete_native) {
@@ -583,36 +545,6 @@ void TabAndroid::SetActiveNavigationEntryTitleForUrl(
     entry->SetTitle(title);
 }
 
-ScopedJavaLocalRef<jobject> TabAndroid::GetFavicon(
-    JNIEnv* env,
-    const JavaParamRef<jobject>& obj) {
-  ScopedJavaLocalRef<jobject> bitmap;
-  favicon::FaviconDriver* favicon_driver =
-      favicon::ContentFaviconDriver::FromWebContents(web_contents_.get());
-
-  if (!favicon_driver)
-    return bitmap;
-
-  // Always return the default favicon in Android.
-  SkBitmap favicon = favicon_driver->GetFavicon().AsBitmap();
-  if (!favicon.empty()) {
-    const float device_scale_factor =
-        display::Screen::GetScreen()->GetPrimaryDisplay().device_scale_factor();
-    int target_size_dip = device_scale_factor * gfx::kFaviconSize;
-    if (favicon.width() != target_size_dip ||
-        favicon.height() != target_size_dip) {
-      favicon =
-          skia::ImageOperations::Resize(favicon,
-                                        skia::ImageOperations::RESIZE_BEST,
-                                        target_size_dip,
-                                        target_size_dip);
-    }
-
-    bitmap = gfx::ConvertToJavaBitmap(&favicon);
-  }
-  return bitmap;
-}
-
 prerender::PrerenderManager* TabAndroid::GetPrerenderManager() const {
   Profile* profile = GetProfile();
   if (!profile)

chrome/browser/android/tab_android.h

@@ -17,7 +17,6 @@
 #include "base/strings/string16.h"
 #include "chrome/browser/android/tab_state.h"
 #include "chrome/browser/sync/glue/synced_tab_delegate_android.h"
-#include "components/favicon/core/favicon_driver_observer.h"
 #include "components/infobars/core/infobar_manager.h"
 #include "components/omnibox/browser/location_bar_model.h"
 #include "components/sessions/core/session_id.h"
@@ -47,8 +46,7 @@ namespace prerender {
 class PrerenderManager;
 }
 
-class TabAndroid : public favicon::FaviconDriverObserver,
-                   public content::WebContentsObserver {
+class TabAndroid : public content::WebContentsObserver {
  public:
   // A Java counterpart will be generated for this enum.
   // GENERATED_JAVA_ENUM_PACKAGE: org.chromium.chrome.browser
@@ -115,13 +113,6 @@ class TabAndroid : public favicon::FaviconDriverObserver,
 
   bool HasPrerenderedUrl(GURL gurl);
 
-  // Overridden from favicon::FaviconDriverObserver:
-  void OnFaviconUpdated(favicon::FaviconDriver* favicon_driver,
-                        NotificationIconType notification_icon_type,
-                        const GURL& icon_url,
-                        bool icon_url_changed,
-                        const gfx::Image& image) override;
-
   // Returns true if this tab is currently presented in the context of custom
   // tabs. Tabs can be moved between different activities so the returned value
   // might change over the lifetime of the tab.

chrome/browser/android/tab_favicon.cc

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/android/tab_favicon.h"
+
+#include "components/favicon/content/content_favicon_driver.h"
+#include "content/public/browser/web_contents.h"
+#include "jni/TabFavicon_jni.h"
+#include "skia/ext/image_operations.h"
+#include "ui/display/display.h"
+#include "ui/display/screen.h"
+#include "ui/gfx/android/java_bitmap.h"
+#include "ui/gfx/favicon_size.h"
+#include "ui/gfx/image/image_skia.h"
+
+using base::android::JavaParamRef;
+using base::android::ScopedJavaLocalRef;
+
+TabFavicon::TabFavicon(JNIEnv* env, const JavaParamRef<jobject>& obj)
+    : jobj_(env, obj) {}
+
+TabFavicon::~TabFavicon() = default;
+
+void TabFavicon::SetWebContents(JNIEnv* env,
+                                const JavaParamRef<jobject>& obj,
+                                const JavaParamRef<jobject>& jweb_contents) {
+  favicon_driver_ = favicon::ContentFaviconDriver::FromWebContents(
+      content::WebContents::FromJavaWebContents(jweb_contents));
+  if (favicon_driver_)
+    favicon_driver_->AddObserver(this);
+}
+
+void TabFavicon::ResetWebContents(JNIEnv* env,
+                                  const JavaParamRef<jobject>& obj) {
+  if (favicon_driver_) {
+    favicon_driver_->RemoveObserver(this);
+    favicon_driver_ = nullptr;
+  }
+}
+
+void TabFavicon::OnDestroyed(JNIEnv* env, const JavaParamRef<jobject>& obj) {
+  delete this;
+}
+
+ScopedJavaLocalRef<jobject> TabFavicon::GetFavicon(
+    JNIEnv* env,
+    const JavaParamRef<jobject>& obj) {
+  ScopedJavaLocalRef<jobject> bitmap;
+
+  if (!favicon_driver_)
+    return bitmap;
+
+  // Always return the default favicon in Android.
+  SkBitmap favicon = favicon_driver_->GetFavicon().AsBitmap();
+  if (!favicon.empty()) {
+    const float device_scale_factor =
+        display::Screen::GetScreen()->GetPrimaryDisplay().device_scale_factor();
+    int target_size_dip = device_scale_factor * gfx::kFaviconSize;
+    if (favicon.width() != target_size_dip ||
+        favicon.height() != target_size_dip) {
+      favicon = skia::ImageOperations::Resize(
+          favicon, skia::ImageOperations::RESIZE_BEST, target_size_dip,
+          target_size_dip);
+    }
+
+    bitmap = gfx::ConvertToJavaBitmap(&favicon);
+  }
+  return bitmap;
+}
+
+void TabFavicon::OnFaviconUpdated(favicon::FaviconDriver* favicon_driver,
+                                  NotificationIconType notification_icon_type,
+                                  const GURL& icon_url,
+                                  bool icon_url_changed,
+                                  const gfx::Image& image) {
+  if (notification_icon_type != NON_TOUCH_LARGEST &&
+      notification_icon_type != TOUCH_LARGEST) {
+    return;
+  }
+
+  SkBitmap favicon = image.AsImageSkia().GetRepresentation(1.0f).GetBitmap();
+  if (favicon.empty())
+    return;
+
+  JNIEnv* env = base::android::AttachCurrentThread();
+  Java_TabFavicon_onFaviconAvailable(env, jobj_,
+                                     gfx::ConvertToJavaBitmap(&favicon));
+}
+
+static jlong JNI_TabFavicon_Init(JNIEnv* env,
+                                 const JavaParamRef<jobject>& obj) {
+  return reinterpret_cast<intptr_t>(new TabFavicon(env, obj));
+}

chrome/browser/android/tab_favicon.h

+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_ANDROID_TAB_FAVICON_H_
+#define CHROME_BROWSER_ANDROID_TAB_FAVICON_H_
+
+#include "base/android/scoped_java_ref.h"
+#include "components/favicon/core/favicon_driver_observer.h"
+
+namespace favicon {
+class FaviconDriver;
+}
+
+// Native Favicon provider for Tab. Managed by Java layer.
+class TabFavicon : public favicon::FaviconDriverObserver {
+ public:
+  TabFavicon(JNIEnv* env, const base::android::JavaParamRef<jobject>& obj);
+  ~TabFavicon() override;
+
+  void SetWebContents(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      const base::android::JavaParamRef<jobject>& jweb_contents);
+  void ResetWebContents(JNIEnv* env,
+                        const base::android::JavaParamRef<jobject>& obj);
+  void OnDestroyed(JNIEnv* env,
+                   const base::android::JavaParamRef<jobject>& obj);
+  base::android::ScopedJavaLocalRef<jobject> GetFavicon(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj);
+
+  // favicon::FaviconDriverObserver
+  void OnFaviconUpdated(favicon::FaviconDriver* favicon_driver,
+                        NotificationIconType notification_icon_type,
+                        const GURL& icon_url,
+                        bool icon_url_changed,
+                        const gfx::Image& image) override;
+
+ private:
+  base::android::ScopedJavaGlobalRef<jobject> jobj_;
+  favicon::FaviconDriver* favicon_driver_;
+};
+
+#endif  // CHROME_BROWSER_ANDROID_TAB_FAVICON_H_