cc: Trigger GPU rasterization based on a per-layer hint

cc/base/switches.cc

Index: cc/base/switches.cc
diff --git a/cc/base/switches.cc b/cc/base/switches.cc
index 1fb7ac98e37d6b3b87e1431a530bd25cd16a291e..f425d7be2b05fc3b39508443a5e91cea0d04899b 100644
--- a/cc/base/switches.cc
+++ b/cc/base/switches.cc
@@ -41,8 +41,15 @@ const char kEnableTopControlsPositionCalculation[] =
 // impl-side painting.
 const char kEnableGPURasterization[] = "enable-gpu-rasterization";
 
+// Always use the Skia GPU backend for drawing layer tiles. Only valid with
+// GPU accelerated compositing + impl-side painting. Overrides the
+// kEnableGPURasterization flag.
+const char kEnableUniversalGPURasterization[] =
+    "enable-universal-gpu-rasterization";
+
 // Disable GPU rasterization, i.e. rasterize on the CPU only.
-// Overrides the kEnableGPURasterization flag.
+// Overrides the kEnableGPURasterization and kEnableUniversalGPURasterization
+// flags.
 const char kDisableGPURasterization[] = "disable-gpu-rasterization";
 
 // The height of the movable top controls.
@@ -165,12 +172,28 @@ bool IsLCDTextEnabled() {
 #endif
 }
 
-bool IsGpuRasterizationEnabled() {
+bool IsHybridGpuRasterizationEnabled() {
+  const CommandLine& command_line = *CommandLine::ForCurrentProcess();
+
+  if (command_line.HasSwitch(switches::kDisableGPURasterization))
+    return false;
+
+  if (command_line.HasSwitch(switches::kEnableUniversalGPURasterization))
+    return false;
+
+  if (command_line.HasSwitch(switches::kEnableGPURasterization))
+    return true;
+
+  return false;
+}
+
+bool IsUniversalGpuRasterizationEnabled() {
   const CommandLine& command_line = *CommandLine::ForCurrentProcess();
 
   if (command_line.HasSwitch(switches::kDisableGPURasterization))
     return false;
-  else if (command_line.HasSwitch(switches::kEnableGPURasterization))
+
+  if (command_line.HasSwitch(switches::kEnableUniversalGPURasterization))
     return true;
 
   return false;