Implement blacklist's force GPU capability in dual GPU machines.

content/gpu/gpu_main.cc

Index: content/gpu/gpu_main.cc
===================================================================
--- content/gpu/gpu_main.cc	(revision 156195)
+++ content/gpu/gpu_main.cc	(working copy)
@@ -22,10 +22,12 @@
 #include "content/gpu/gpu_process.h"
 #include "content/public/common/content_client.h"
 #include "content/public/common/content_switches.h"
+#include "content/public/common/gpu_switching_option.h"
 #include "content/public/common/main_function_params.h"
 #include "crypto/hmac.h"
 #include "ui/gl/gl_surface.h"
 #include "ui/gl/gl_switches.h"
+#include "ui/gl/gpu_switching_manager.h"
 
 #if defined(OS_WIN)
 #include "content/common/gpu/media/dxva_video_decode_accelerator.h"
@@ -73,6 +75,15 @@
 #endif
   }
 
+  if (command_line.HasSwitch(switches::kGpuSwitching)) {
+    std::string option = command_line.GetSwitchValueASCII(
+        switches::kGpuSwitching);
+    if (option == switches::kGpuSwitchingOptionNameForceDiscrete)
+      gfx::GpuSwitchingManager::GetInstance()->ForceUseOfDiscreteGpu();
+    else if (option == switches::kGpuSwitchingOptionNameForceIntegrated)
+      gfx::GpuSwitchingManager::GetInstance()->ForceUseOfIntegratedGpu();
+  }
+
   // Initialization of the OpenGL bindings may fail, in which case we
   // will need to tear down this process. However, we can not do so
   // safely until the IPC channel is set up, because the detection of