Enable V8 idle notification after commit.

Enable the notification by default. Change flag
--send-v8-idle-notification-after-commit to
--enable-v8-idle-notification-after-commit. Add new flag
--disable-v8-idle-notification-after-commit to override enable or
default.

R=jochen@chromium.org,hpayer@chromium.org,jamesr@chromium.org,danno@chromium.org
BUG=414815

Review URL: https://codereview.chromium.org/566733004

Cr-Commit-Position: refs/heads/master@{#295540}

content/browser/renderer_host/render_process_host_impl.cc

@@ -1091,6 +1091,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kDisableTouchAdjustment,
     switches::kDisableTouchDragDrop,
     switches::kDisableTouchEditing,
+    switches::kDisableV8IdleNotificationAfterCommit,
     switches::kDisableZeroCopy,
     switches::kDomAutomationController,
     switches::kEnableBeginFrameScheduling,
@@ -1128,6 +1129,7 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kEnableThreadedCompositing,
     switches::kEnableTouchDragDrop,
     switches::kEnableTouchEditing,
+    switches::kEnableV8IdleNotificationAfterCommit,
     switches::kEnableViewport,
     switches::kEnableViewportMeta,
     switches::kEnableVtune,
@@ -1153,7 +1155,6 @@ void RenderProcessHostImpl::PropagateBrowserCommandLineToRenderer(
     switches::kRegisterPepperPlugins,
     switches::kRendererAssertTest,
     switches::kRendererStartupDialog,
-    switches::kSendV8IdleNotificationAfterCommit,
     switches::kShowPaintRects,
     switches::kSitePerProcess,
     switches::kStatsCollectionController,

content/public/common/content_switches.cc

@@ -250,6 +250,11 @@ const char kDisableSoftwareRasterizer[]     = "disable-software-rasterizer";
 // Disable multithreaded GPU compositing of web content.
 const char kDisableThreadedCompositing[]     = "disable-threaded-compositing";
 
+// Disable V8 idle notification after commit.
+// Overrides kEnableV8IdleNotificationAfterCommit.
+const char kDisableV8IdleNotificationAfterCommit[] =
+    "disable-v8-idle-notification-after-commit";
+
 // Don't enforce the same-origin policy. (Used by people testing their sites.)
 const char kDisableWebSecurity[]            = "disable-web-security";
 
@@ -455,6 +460,14 @@ const char kEnableUserMediaScreenCapturing[] =
 // Enables streaming scripts to V8 while loading.
 const char kEnableV8ScriptStreaming[] = "enable-v8-script-streaming";
 
+// Send a notification from RenderWidgetCompositor to V8 to do idle work
+// (e.g. garbage collection) after the commit until the beginning of the next
+// frame.  This moves the work off the critical path where compositor is waiting
+// for the main thread. The flag is experimental until the implementation of the
+// V8 idle handler is completed.
+const char kEnableV8IdleNotificationAfterCommit[] =
+    "enable-v8-idle-notification-after-commit";
+
 // Enables the use of the @viewport CSS rule, which allows
 // pages to control aspects of their own layout. This also turns on touch-screen
 // pinch gestures.
@@ -692,14 +705,6 @@ const char kSandboxIPCProcess[]             = "sandbox-ipc";
 // Defaults to disabled.
 const char kScrollEndEffect[] = "scroll-end-effect";
 
-// Send a notification from RenderWidgetCompositor to V8 to do idle work
-// (e.g. garbage collection) after the commit until the beginning of the next
-// frame.  This moves the work off the critical path where compositor is waiting
-// for the main thread. The flag is experimental until the implementation of the
-// V8 idle handler is completed.
-const char kSendV8IdleNotificationAfterCommit[] =
-    "send-v8-idle-notification-after-commit";
-
 // Visibly render a border around paint rects in the web page to help debug
 // and study painting behavior.
 const char kShowPaintRects[]                = "show-paint-rects";

content/public/common/content_switches.h

@@ -82,6 +82,7 @@ CONTENT_EXPORT extern const char kDisableSingleThreadProxyScheduler[];
 CONTENT_EXPORT extern const char kDisableSmoothScrolling[];
 CONTENT_EXPORT extern const char kDisableSoftwareRasterizer[];
 CONTENT_EXPORT extern const char kDisableThreadedCompositing[];
+extern const char kDisableV8IdleNotificationAfterCommit[];
 CONTENT_EXPORT extern const char kDisableWebSecurity[];
 extern const char kDisableXSLT[];
 extern const char kDisableXSSAuditor[];
@@ -134,6 +135,7 @@ CONTENT_EXPORT extern const char kEnableTracing[];
 CONTENT_EXPORT extern const char kEnableTracingOutput[];
 CONTENT_EXPORT extern const char kEnableUserMediaScreenCapturing[];
 extern const char kEnableV8ScriptStreaming[];
+extern const char kEnableV8IdleNotificationAfterCommit[];
 CONTENT_EXPORT extern const char kEnableViewport[];
 CONTENT_EXPORT extern const char kEnableViewportMeta[];
 CONTENT_EXPORT extern const char kMainFrameResizesAreOrientationChanges[];
@@ -198,7 +200,6 @@ CONTENT_EXPORT extern const char kRendererProcessLimit[];
 CONTENT_EXPORT extern const char kRendererStartupDialog[];
 extern const char kSandboxIPCProcess[];
 CONTENT_EXPORT extern const char kScrollEndEffect[];
-extern const char kSendV8IdleNotificationAfterCommit[];
 extern const char kShowPaintRects[];
 CONTENT_EXPORT extern const char kSingleProcess[];
 CONTENT_EXPORT extern const char kSitePerProcess[];

content/renderer/gpu/render_widget_compositor.cc

@@ -423,11 +423,13 @@ RenderWidgetCompositor::RenderWidgetCompositor(RenderWidget* widget,
                                                bool threaded)
     : threaded_(threaded),
       widget_(widget),
-      send_v8_idle_notification_after_commit_(false) {
+      send_v8_idle_notification_after_commit_(true) {
   CommandLine* cmd = CommandLine::ForCurrentProcess();
 
-  if (cmd->HasSwitch(switches::kSendV8IdleNotificationAfterCommit))
+  if (cmd->HasSwitch(switches::kEnableV8IdleNotificationAfterCommit))
     send_v8_idle_notification_after_commit_ = true;
+  if (cmd->HasSwitch(switches::kDisableV8IdleNotificationAfterCommit))
+    send_v8_idle_notification_after_commit_ = false;
 }
 
 RenderWidgetCompositor::~RenderWidgetCompositor() {}