Add an API for plumbing screenshots from C++ -> Java

Uses ThumbnailCache's DecompressThumbnailFromFile to read, decompress
and return tab thumbnails on the Java side.

Change-Id: Ia3905cf2f3aa859318897db0fcb2d1b489a7827a
Reviewed-on: https://chromium-review.googlesource.com/c/1423702Reviewed-by: Matthew Jones <mdjones@chromium.org>
Commit-Queue: Yusuf Ozuysal <yusufo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#626147}

chrome/android/java/src/org/chromium/chrome/browser/compositor/layouts/content/TabContentManager.java

@@ -10,6 +10,7 @@ import android.graphics.Canvas;
 import android.view.View;
 import android.view.ViewGroup.MarginLayoutParams;
 
+import org.chromium.base.Callback;
 import org.chromium.base.CommandLine;
 import org.chromium.base.annotations.CalledByNative;
 import org.chromium.base.annotations.JNINamespace;
@@ -212,6 +213,23 @@ public class TabContentManager {
         return nativeHasFullCachedThumbnail(mNativeTabContentManager, tabId);
     }
 
+    /**
+     * Call to get a thumbnail for a given tab ID from disk through a {@link Callback}. If there is
+     * no up to date thumbnail on the cache for the given tab, callback returns a null result.
+     * Currently this read a compressed file from disk and sends the Bitmap over the
+     * JNI boundary after decompressing. In its current form, should be used for experimental
+     * purposes only.
+     * TODO(yusufo): Change the plumbing so that at the least a {@link android.net.Uri} is send
+     * over JNI of an uncompressed file on disk.
+     * @param tabID The ID of the tab.
+     * @param callback The callback to send the {@link Bitmap} with.
+     */
+    public void getTabThumbnailWithCallback(int tabID, Callback<Bitmap> callback) {
+        if (mNativeTabContentManager == 0 || !mSnapshotsEnabled) return;
+
+        nativeGetTabThumbnailWithCallback(mNativeTabContentManager, tabID, callback);
+    }
+
     /**
      * Cache the content of a tab as a thumbnail.
      * @param tab The tab whose content we will cache.
@@ -302,5 +320,7 @@ public class TabContentManager {
     private native void nativeUpdateVisibleIds(
             long nativeTabContentManager, int[] priority, int primaryTabId);
     private native void nativeRemoveTabThumbnail(long nativeTabContentManager, int tabId);
+    private native void nativeGetTabThumbnailWithCallback(
+            long nativeTabContentManager, int tabId, Callback<Bitmap> callback);
     private static native void nativeDestroy(long nativeTabContentManager);
 }

chrome/browser/android/compositor/tab_content_manager.cc

@@ -10,6 +10,7 @@
 #include <memory>
 #include <utility>
 
+#include "base/android/callback_android.h"
 #include "base/android/jni_android.h"
 #include "base/android/jni_string.h"
 #include "base/android/scoped_java_ref.h"
@@ -297,6 +298,18 @@ void TabContentManager::RemoveTabThumbnail(JNIEnv* env,
   NativeRemoveTabThumbnail(tab_id);
 }
 
+void TabContentManager::GetTabThumbnailWithCallback(
+    JNIEnv* env,
+    const base::android::JavaParamRef<jobject>& obj,
+    jint tab_id,
+    const base::android::JavaParamRef<jobject>& j_callback) {
+  thumbnail_cache_->DecompressThumbnailFromFile(
+      tab_id, base::BindRepeating(
+                  &TabContentManager::TabThumbnailAvailableFromDisk,
+                  weak_factory_.GetWeakPtr(),
+                  base::android::ScopedJavaGlobalRef<jobject>(j_callback)));
+}
+
 void TabContentManager::OnUIResourcesWereEvicted() {
   thumbnail_cache_->OnUIResourcesWereEvicted();
 }
@@ -320,6 +333,17 @@ void TabContentManager::PutThumbnailIntoCache(int tab_id,
     thumbnail_cache_->Put(tab_id, bitmap, thumbnail_scale);
 }
 
+void TabContentManager::TabThumbnailAvailableFromDisk(
+    base::android::ScopedJavaGlobalRef<jobject> j_callback,
+    bool result,
+    SkBitmap bitmap) {
+  ScopedJavaLocalRef<jobject> j_bitmap;
+  if (!bitmap.isNull() && result)
+    j_bitmap = gfx::ConvertToJavaBitmap(&bitmap);
+
+  RunObjectCallbackAndroid(j_callback, j_bitmap);
+}
+
 // ----------------------------------------------------------------------------
 // Native JNI methods
 // ----------------------------------------------------------------------------

chrome/browser/android/compositor/tab_content_manager.h

@@ -11,6 +11,7 @@
 
 #include "base/android/jni_android.h"
 #include "base/android/jni_weak_ref.h"
+#include "base/android/scoped_java_ref.h"
 #include "base/containers/flat_map.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
@@ -96,6 +97,11 @@ class TabContentManager : public ThumbnailCacheObserver {
                           const base::android::JavaParamRef<jobject>& obj,
                           jint tab_id);
   void OnUIResourcesWereEvicted();
+  void GetTabThumbnailWithCallback(
+      JNIEnv* env,
+      const base::android::JavaParamRef<jobject>& obj,
+      jint tab_id,
+      const base::android::JavaParamRef<jobject>& j_callback);
 
   // ThumbnailCacheObserver implementation;
   void OnFinishedThumbnailRead(TabId tab_id) override;
@@ -113,6 +119,11 @@ class TabContentManager : public ThumbnailCacheObserver {
                              float thumbnail_scale,
                              const SkBitmap& bitmap);
 
+  void TabThumbnailAvailableFromDisk(
+      base::android::ScopedJavaGlobalRef<jobject> j_callback,
+      bool result,
+      SkBitmap bitmap);
+
   std::unique_ptr<ThumbnailCache> thumbnail_cache_;
   ThumbnailLayerMap static_layer_cache_;
   LayerMap live_layer_list_;