Turn on GPU rasterization when --enable-bleeding-edge-rendering-fast-paths is true.

cc/base/switches.cc

 // Copyright (c) 2012 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 "cc/base/switches.h"
 
 #include "base/command_line.h"
 
 namespace cc {
 namespace switches {
@@ skipping 12 matching lines @@
 const char kDisableCompositedAntialiasing[] =
     "disable-composited-antialiasing";
 
 // Paint content on the main thread instead of the compositor thread.
 // Overrides the kEnableImplSidePainting flag.
 const char kDisableImplSidePainting[] = "disable-impl-side-painting";
 
 // Enables LCD text.
 const char kEnableLCDText[] = "enable-lcd-text";
 
+// Enable bleeding-edge code to make Chrome draw content faster. The changes
+// behind this path are very likely to break lots of content.
+// ** DO NOT use this flag unless you know what you are doing. **
+// This is the same flag as the one defined in
+//  content/public/common/content_switches.cc.

[jamesr, 2014/02/22 00:30:04]

no.  if you want the behavior controlled by a content::, set it from content
code. you probably want content/renderer/gpu/render_widget_compositor.cc to set
the appropriate setting or, failing that, populate the appropriate flag for
render process's command line in render_process_host_impl

[chrishtr, 2014/02/22 00:33:11]

Ok, I  can do that, thanks for the pointer.

I don't understand these dependencies though. Why can
content/renderer/gpu/render_widget_compositor.cc see a content switch and also
this file, but not vice versa?

[chrishtr, 2014/02/22 00:38:43]

Done.

+const char kEnableBleedingEdgeRenderingFastPaths[] =
+    "enable-bleeding-edge-rendering-fast-paths";
+
 // Paint content on the compositor thread instead of the main thread.
 const char kEnableImplSidePainting[] = "enable-impl-side-painting";
 
 const char kEnableTopControlsPositionCalculation[] =
     "enable-top-controls-position-calculation";
 
 // Allow heuristics to determine when a layer tile should be drawn with
 // the Skia GPU backend.  Only valid with GPU accelerated compositing +
 // impl-side painting.
 const char kEnableGPURasterization[] = "enable-gpu-rasterization";
@@ skipping 122 matching lines @@
 #endif
 }
 
 bool IsGpuRasterizationEnabled() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kDisableGPURasterization))
     return false;
   else if (command_line.HasSwitch(switches::kEnableGPURasterization))
     return true;
+  else if (command_line.HasSwitch(
+               switches::kEnableBleedingEdgeRenderingFastPaths))
+    return true;
 
   return false;
 }
 
 bool IsImplSidePaintingEnabled() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kDisableImplSidePainting))
     return false;
   else if (command_line.HasSwitch(switches::kEnableImplSidePainting))
@@ skipping 12 matching lines @@
   if (command_line.HasSwitch(switches::kDisableMapImage))
     return false;
   else if (command_line.HasSwitch(switches::kEnableMapImage))
     return true;
 
   return false;
 }
 
 }  // namespace switches
 }  // namespace cc