content: Add command line flag for native GPU memory buffers.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 034b3f5a995b4b843ad9994968798486dd122840..38683435ba0f69c1ad548fa34053fe55351b0869 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -4,6 +4,9 @@
 
 #include "content/browser/browser_main_loop.h"
 
+#include <string>
+#include <vector>
+
 #include "base/bind.h"
 #include "base/command_line.h"
 #include "base/debug/trace_event.h"
@@ -40,6 +43,7 @@
 #include "content/browser/time_zone_monitor.h"
 #include "content/browser/webui/content_web_ui_controller_factory.h"
 #include "content/browser/webui/url_data_manager.h"
+#include "content/common/gpu/client/gpu_memory_buffer_impl.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/browser_shutdown.h"
 #include "content/public/browser/content_browser_client.h"
@@ -430,6 +434,29 @@ void BrowserMainLoop::EarlyInitialization() {
   }
 #endif  // !defined(OS_IOS)
 
+  std::vector<gfx::GpuMemoryBufferType> supported_types;
+  GpuMemoryBufferImpl::GetSupportedTypes(&supported_types);
+  DCHECK(!supported_types.empty());
+
+  // The default preferred type is always the first one in list.
+  gfx::GpuMemoryBufferType type = supported_types[0];
+
+  if (parsed_command_line_.HasSwitch(switches::kUseGpuMemoryBuffer)) {
+    std::string requested_type_name = parsed_command_line_.GetSwitchValueASCII(
+        switches::kUseGpuMemoryBuffer);
+    gfx::GpuMemoryBufferType requested_type =
+        GpuMemoryBufferImpl::GetNamedType(requested_type_name);
+    if (std::find(supported_types.begin(),
+                  supported_types.end(),
+                  requested_type) != supported_types.end()) {
+      type = requested_type;
+    } else {
+      LOG(ERROR) << "Requested GPU memory buffer type is not supported.";
+    }
+  }
+
+  GpuMemoryBufferImpl::SetPreferredType(type);
+
   if (parts_)
     parts_->PostEarlyInitialization();
 }