Make VoiceSearchTabHelper a purely native object

There's no reason for VoiceSearchTabHelper to exist as a Java entity. It
simply routes a WebContentsObserver callback originating in native
code back to some more native code for processing, and has no Java
dependencies.

Review URL: https://codereview.chromium.org/979813004

Cr-Commit-Position: refs/heads/master@{#319186}

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

@@ -166,7 +166,6 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
     // Content layer Observers and Delegates
     private ContentViewClient mContentViewClient;
     private WebContentsObserver mWebContentsObserver;
-    private VoiceSearchTabHelper mVoiceSearchTabHelper;
     private TabChromeWebContentsDelegateAndroid mWebContentsDelegate;
     private DomDistillerFeedbackReporter mDomDistillerFeedbackReporter;
 
@@ -1437,7 +1436,6 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
 
         mWebContentsDelegate = createWebContentsDelegate();
         mWebContentsObserver = new TabWebContentsObserver(mContentViewCore.getWebContents());
-        mVoiceSearchTabHelper = new VoiceSearchTabHelper(mContentViewCore.getWebContents());
 
         if (mContentViewClient != null) mContentViewCore.setContentViewClient(mContentViewClient);
 
@@ -1878,11 +1876,6 @@ public class Tab implements ViewGroup.OnHierarchyChangeListener,
             mWebContentsObserver = null;
         }
 
-        if (mVoiceSearchTabHelper != null) {
-            mVoiceSearchTabHelper.destroy();
-            mVoiceSearchTabHelper = null;
-        }
-
         assert mNativeTabAndroid != 0;
         nativeDestroyWebContents(mNativeTabAndroid, deleteNativeWebContents);
     }

chrome/android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java

-// Copyright 2014 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;
-
-import org.chromium.content_public.browser.WebContents;
-import org.chromium.content_public.browser.WebContentsObserver;
-
-/**
- * Tab helper to toggle media autoplay for voice URL searches.
- */
-public class VoiceSearchTabHelper extends WebContentsObserver {
-    private final WebContents mWebContents;
-
-    /**
-     * Create an instance of VoiceSearchTabHelper.
-     *
-     * @param webContents WebContents to update media autoplay status.
-     */
-    public VoiceSearchTabHelper(WebContents webContents) {
-        super(webContents);
-        mWebContents = webContents;
-    }
-
-    @Override
-    public void navigationEntryCommitted() {
-        nativeUpdateAutoplayStatus(mWebContents);
-    }
-
-    private native void nativeUpdateAutoplayStatus(WebContents webContents);
-}

chrome/browser/android/chrome_jni_registrar.cc

@@ -236,7 +236,6 @@ static base::android::RegistrationMethod kChromeRegisteredMethods[] = {
     {"UmaSessionStats", RegisterUmaSessionStats},
     {"UrlUtilities", RegisterUrlUtilities},
     {"Variations", variations::android::RegisterVariations},
-    {"VoiceSearchTabHelper", RegisterVoiceSearchTabHelper},
     {"WebsitePreferenceBridge", RegisterWebsitePreferenceBridge},
     {"WebsiteSettingsPopupAndroid",
      WebsiteSettingsPopupAndroid::RegisterWebsiteSettingsPopupAndroid},

chrome/browser/android/voice_search_tab_helper.cc

@@ -10,38 +10,36 @@
 #include "content/public/browser/web_contents.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/web_preferences.h"
-#include "jni/VoiceSearchTabHelper_jni.h"
 
-using content::WebContents;
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(VoiceSearchTabHelper);
 
-// Register native methods
-bool RegisterVoiceSearchTabHelper(JNIEnv* env) {
-  return RegisterNativesImpl(env);
+VoiceSearchTabHelper::VoiceSearchTabHelper(content::WebContents* contents)
+    : content::WebContentsObserver(contents) {
+  gesture_requirement_for_playback_disabled_ =
+      base::CommandLine::ForCurrentProcess()->HasSwitch(
+          switches::kDisableGestureRequirementForMediaPlayback);
 }
 
-static void UpdateAutoplayStatus(JNIEnv* env,
-                                 jobject obj,
-                                 jobject j_web_contents) {
+VoiceSearchTabHelper::~VoiceSearchTabHelper() {
+}
+
+void VoiceSearchTabHelper::NavigationEntryCommitted(
+    const content::LoadCommittedDetails& load_details) {
   // In the case where media autoplay has been disabled by default (e.g. in
   // performance media tests) do not update it based on navigation changes.
-  const base::CommandLine& command_line =
-      *base::CommandLine::ForCurrentProcess();
-  if (command_line.HasSwitch(
-      switches::kDisableGestureRequirementForMediaPlayback))
+  if (gesture_requirement_for_playback_disabled_)
     return;
 
-  WebContents* web_contents = WebContents::FromJavaWebContents(j_web_contents);
-  content::RenderViewHost* host = web_contents->GetRenderViewHost();
+  content::RenderViewHost* host = web_contents()->GetRenderViewHost();
   content::WebPreferences prefs = host->GetWebkitPreferences();
 
   bool gesture_required =
-      !google_util::IsGoogleSearchUrl(web_contents->GetLastCommittedURL());
+      !google_util::IsGoogleSearchUrl(web_contents()->GetLastCommittedURL());
 
   if (gesture_required != prefs.user_gesture_required_for_media_playback) {
     // TODO(chrishtr): this is wrong. user_gesture_required_for_media_playback
     // will be reset the next time a preference changes.
-    prefs.user_gesture_required_for_media_playback =
-        !google_util::IsGoogleSearchUrl(web_contents->GetLastCommittedURL());
+    prefs.user_gesture_required_for_media_playback = gesture_required;
     host->UpdateWebkitPreferences(prefs);
   }
 }

chrome/browser/android/voice_search_tab_helper.h

@@ -5,8 +5,28 @@
 #ifndef CHROME_BROWSER_ANDROID_VOICE_SEARCH_TAB_HELPER_H_
 #define CHROME_BROWSER_ANDROID_VOICE_SEARCH_TAB_HELPER_H_
 
-#include "base/android/jni_android.h"
+#include "base/macros.h"
+#include "content/public/browser/web_contents_observer.h"
+#include "content/public/browser/web_contents_user_data.h"
 
-bool RegisterVoiceSearchTabHelper(JNIEnv* env);
+// Tab helper to toggle media autoplay for voice URL searches.
+class VoiceSearchTabHelper
+    : public content::WebContentsObserver,
+      public content::WebContentsUserData<VoiceSearchTabHelper> {
+ public:
+  ~VoiceSearchTabHelper() override;
+
+  // content::WebContentsObserver overrides.
+  void NavigationEntryCommitted(
+      const content::LoadCommittedDetails& load_details) override;
+
+ private:
+  explicit VoiceSearchTabHelper(content::WebContents* contents);
+  friend class content::WebContentsUserData<VoiceSearchTabHelper>;
+
+  bool gesture_requirement_for_playback_disabled_;
+
+  DISALLOW_COPY_AND_ASSIGN(VoiceSearchTabHelper);
+};
 
 #endif  // CHROME_BROWSER_ANDROID_VOICE_SEARCH_TAB_HELPER_H_

chrome/browser/ui/tab_helpers.cc

@@ -39,6 +39,7 @@
 #include "content/public/browser/web_contents.h"
 
 #if defined(OS_ANDROID)
+#include "chrome/browser/android/voice_search_tab_helper.h"
 #include "chrome/browser/android/webapps/single_tab_mode_tab_helper.h"
 #include "chrome/browser/enhanced_bookmarks/android/enhanced_bookmark_tab_helper.h"
 #include "chrome/browser/ui/android/context_menu_helper.h"
@@ -161,6 +162,7 @@ void TabHelpers::AttachTabHelpers(WebContents* web_contents) {
   ContextMenuHelper::CreateForWebContents(web_contents);
   EnhancedBookmarkTabHelper::CreateForWebContents(web_contents);
   SingleTabModeTabHelper::CreateForWebContents(web_contents);
+  VoiceSearchTabHelper::CreateForWebContents(web_contents);
   WindowAndroidHelper::CreateForWebContents(web_contents);
 #else
   extensions::ChromeExtensionWebContentsObserver::CreateForWebContents(

chrome/chrome_browser.gypi

@@ -1665,7 +1665,6 @@
       'android/java/src/org/chromium/chrome/browser/TtsPlatformImpl.java',
       'android/java/src/org/chromium/chrome/browser/UrlUtilities.java',
       'android/java/src/org/chromium/chrome/browser/util/FeatureUtilities.java',
-      'android/java/src/org/chromium/chrome/browser/VoiceSearchTabHelper.java',
       'android/java/src/org/chromium/chrome/browser/WebsiteSettingsPopup.java',
       'android/java/src/org/chromium/chrome/browser/infobar/AppBannerInfoBar.java',
       'android/java/src/org/chromium/chrome/browser/infobar/AccountChooserInfoBar.java',