Simplify pinch flags.

At present, we have two flags to enable two different pinch models:

enable-pinch => enables Android style zoom
enable-pinch + enable-pinch-in-compositor => enables chrome linux/win accelerated zoom

This CL rationalizes the flags so that

enable-css-transform-pinch => enables Android style zoom
enable-pinch => enables chrome linux/win accelerated zoom

and the latter can be controlled via about:flags.

BUG=
NOTRY=TRUE


Review URL: https://chromiumcodereview.appspot.com/11348353

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@171309 0039d316-1c4b-4281-b951-d872f2087c98

cc/switches.cc

@@ -21,10 +21,6 @@ const char kEnablePartialSwap[]             = "enable-partial-swap";
 
 const char kEnablePerTilePainting[]         = "enable-per-tile-painting";
 
-// Enables an alternative pinch-zoom gesture support, via the threaded
-// compositor.
-const char kEnablePinchInCompositor[]       = "enable-pinch-in-compositor";
-
 // Number of worker threads used to rasterize content.
 const char kNumRasterThreads[] = "num-raster-threads";
 

cc/switches.h

@@ -20,7 +20,6 @@ CC_EXPORT extern const char kDisableThreadedAnimation[];
 CC_EXPORT extern const char kEnableImplSidePainting[];
 CC_EXPORT extern const char kEnablePartialSwap[];
 CC_EXPORT extern const char kEnablePerTilePainting[];
-CC_EXPORT extern const char kEnablePinchInCompositor[];
 CC_EXPORT extern const char kJankInsteadOfCheckerboard[];
 CC_EXPORT extern const char kNumRasterThreads[];
 CC_EXPORT extern const char kShowPropertyChangedRects[];

chrome/browser/about_flags.cc

@@ -894,7 +894,7 @@ const Experiment kExperiments[] = {
     "enable-pinch",
     IDS_FLAGS_ENABLE_PINCH_SCALE_NAME,
     IDS_FLAGS_ENABLE_PINCH_SCALE_DESCRIPTION,
-    kOsAll,
+    kOsLinux | kOsWin | kOsCrOS,
     SINGLE_VALUE_TYPE(switches::kEnablePinch),
   },
   {

chrome/browser/chromeos/login/login_utils.cc

@@ -815,7 +815,6 @@ std::string LoginUtilsImpl::GetOffTheRecordCommandLine(
       ash::switches::kAshDisablePanelFitting,
       cc::switches::kDisableThreadedAnimation,
       cc::switches::kEnablePartialSwap,
-      cc::switches::kEnablePinchInCompositor,
       chromeos::switches::kDbusStub,
       chromeos::switches::kEnableNewNetworkHandlers,
       gfx::switches::kEnableBrowserTextSubpixelPositioning,

content/browser/android/content_startup_flags.cc

@@ -51,7 +51,7 @@ void SetContentCommandLineFlags(int max_render_process_count) {
       switches::kEnableCompositingForFixedPosition);
 
   parsed_command_line->AppendSwitch(switches::kEnableGestureTapHighlight);
-  parsed_command_line->AppendSwitch(switches::kEnablePinch);
+  parsed_command_line->AppendSwitch(switches::kEnableCssTransformPinch);
 
   // Run the GPU service as a thread in the browser instead of as a
   // standalone process.

content/browser/web_contents/web_contents_impl.cc

@@ -653,7 +653,7 @@ WebPreferences WebContentsImpl::GetWebkitPrefs(RenderViewHost* rvh,
   }
 
   prefs.apply_page_scale_factor_in_compositor =
-      command_line.HasSwitch(cc::switches::kEnablePinchInCompositor);
+      command_line.HasSwitch(switches::kEnablePinch);
   prefs.per_tile_painting_enabled =
       command_line.HasSwitch(cc::switches::kEnablePerTilePainting);
   prefs.accelerated_animation_enabled =

content/public/common/content_switches.cc

@@ -308,9 +308,12 @@ const char kEnableMonitorProfile[]          = "enable-monitor-profile";
 // that support it.
 const char kEnableUIReleaseFrontSurface[] = "enable-ui-release-front-surface";
 
-// Enables touch-screen pinch gestures.
+// Enables compositor-accelerated touch-screen pinch gestures.
 const char kEnablePinch[]                   = "enable-pinch";
 
+// Enables Android-style touch-screen pinch gestures.
+const char kEnableCssTransformPinch[]       = "enable-css-transform-pinch";
+
 // Enable caching of pre-parsed JS script data.  See http://crbug.com/32407.
 const char kEnablePreparsedJsCaching[]      = "enable-preparsed-js-caching";
 

content/public/common/content_switches.h

@@ -108,6 +108,7 @@ CONTENT_EXPORT extern const char kUseFakeDeviceForMediaStream[];
 extern const char kEnableMonitorProfile[];
 extern const char kEnableUIReleaseFrontSurface[];
 extern const char kEnablePinch[];
+extern const char kEnableCssTransformPinch[];
 extern const char kEnablePreparsedJsCaching[];
 CONTENT_EXPORT extern const char kEnablePrivilegedWebGLExtensions[];
 extern const char kEnablePruneGpuCommandBuffers[];

content/renderer/render_view_impl.cc

@@ -3185,25 +3185,19 @@ void RenderViewImpl::ProcessViewLayoutFlags(const CommandLine& command_line) {
 
 void RenderViewImpl::ProcessAcceleratedPinchZoomFlags(
     const CommandLine& command_line) {
-  bool enable_viewport =
-      command_line.HasSwitch(switches::kEnableViewport);
-  bool enable_pinch = enable_viewport ||
-                      command_line.HasSwitch(switches::kEnablePinch);
-  bool enable_pinch_in_compositor =
-      command_line.HasSwitch(cc::switches::kEnablePinchInCompositor);
+  if (!webview()->isAcceleratedCompositingActive())
+    return;
 
-  if (!enable_pinch &&
-      webview()->isAcceleratedCompositingActive() &&
-      webkit_preferences_.apply_default_device_scale_factor_in_compositor &&
-      device_scale_factor_ != 1) {
-    // Page scaling is disabled by default when applying a scale factor in the
-    // compositor since they are currently incompatible.
-    webview()->setPageScaleFactorLimits(1, 1);
-  }
+  bool enable_viewport = command_line.HasSwitch(switches::kEnableViewport);
+  bool enable_pinch = command_line.HasSwitch(switches::kEnablePinch);
 
-  if (enable_pinch_in_compositor &&
-      webview()->isAcceleratedCompositingActive())
+  if (enable_viewport)
+    return;
+
+  if (enable_pinch)
     webview()->setPageScaleFactorLimits(1, 4);
+  else
+    webview()->setPageScaleFactorLimits(1, 1);
 }
 
 void RenderViewImpl::didStartProvisionalLoad(WebFrame* frame) {