Add PERSISTENT_MAP usage for GpuMemoryBuffers.

content/browser/gpu/browser_gpu_channel_host_factory.cc

Index: content/browser/gpu/browser_gpu_channel_host_factory.cc
diff --git a/content/browser/gpu/browser_gpu_channel_host_factory.cc b/content/browser/gpu/browser_gpu_channel_host_factory.cc
index 205542cdc81e918839841fbbeb55d99e16c6cadd..a2e4627e202fb09ad1c1bf237268d059600da893 100644
--- a/content/browser/gpu/browser_gpu_channel_host_factory.cc
+++ b/content/browser/gpu/browser_gpu_channel_host_factory.cc
@@ -16,6 +16,7 @@
 #include "content/browser/gpu/gpu_process_host.h"
 #include "content/browser/gpu/gpu_surface_tracker.h"
 #include "content/common/child_process_host_impl.h"
+#include "content/common/gpu/client/gpu_memory_buffer_impl_shared_memory.h"
 #include "content/common/gpu/gpu_memory_buffer_factory.h"
 #include "content/common/gpu/gpu_messages.h"
 #include "content/public/browser/browser_thread.h"
@@ -254,16 +255,26 @@ bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferFactoryUsageEnabled(
 }
 
 // static
-uint32 BrowserGpuChannelHostFactory::GetImageTextureTarget() {
-  if (!IsGpuMemoryBufferFactoryUsageEnabled(gfx::GpuMemoryBuffer::MAP))
+uint32 BrowserGpuChannelHostFactory::GetImageTextureTarget(
+    gfx::GpuMemoryBuffer::Format format,
+    gfx::GpuMemoryBuffer::Usage usage) {
+  if (!IsGpuMemoryBufferFactoryUsageEnabled(usage))
     return GL_TEXTURE_2D;
 
   std::vector<gfx::GpuMemoryBufferType> supported_types;
   GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);
   DCHECK(!supported_types.empty());
 
-  // The GPU service will always use the preferred type.
+  // The GPU service will always use the preferred type, if the |format| and
+  // |usage| allows.
   gfx::GpuMemoryBufferType type = supported_types[0];
+  // If the native buffer type does not support the |format| and |usage| then
+  // we must fallback to shared memory buffers, which do support them.

[reveman, 2015/05/20 14:26:07]

The condition for |format| and |usage| not being supported is exactly the same
as the UsageEnabled(usage) check above. If the factory is not going to be used
for this usage+format then GL_TEXTURE_2D should be returned. No need to mention
anything about a shared memory implementation here.

[danakj, 2015/05/20 17:51:14]

Done.

+  if (!IsGpuMemoryBufferConfigurationSupportedInternal(format, usage)) {
+    DCHECK(GpuMemoryBufferImplSharedMemory::IsFormatSupported(format));
+    DCHECK(GpuMemoryBufferImplSharedMemory::IsUsageSupported(usage));
+    type = gfx::SHARED_MEMORY_BUFFER;

[reveman, 2015/05/20 14:26:08]

I don't see a good reason for handling this differently than the
UsageEnabled(usage) check. Please replace this line with "return GL_TEXTURE_2D;"
and remove the DCHECKs.

[danakj, 2015/05/20 17:51:14]

Done.

+  }
 
   switch (type) {
     case gfx::SURFACE_TEXTURE_BUFFER:
@@ -467,11 +478,18 @@ void BrowserGpuChannelHostFactory::AddFilterOnIO(
 bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferConfigurationSupported(
     gfx::GpuMemoryBuffer::Format format,
     gfx::GpuMemoryBuffer::Usage usage) {
+  return IsGpuMemoryBufferConfigurationSupportedInternal(format, usage);
+}
+
+// static
+bool BrowserGpuChannelHostFactory::
+    IsGpuMemoryBufferConfigurationSupportedInternal(
+        gfx::GpuMemoryBuffer::Format format,
+        gfx::GpuMemoryBuffer::Usage usage) {
   // Return early if usage is not enabled.
   if (!IsGpuMemoryBufferFactoryUsageEnabled(usage))

[reveman, 2015/05/20 14:26:07]

Please remove this check from this helper function so it's not done twice.

[danakj, 2015/05/20 17:51:14]

Done.

     return false;
 
-  // Preferred type is always used by factory.
   std::vector<gfx::GpuMemoryBufferType> supported_types;
   GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);

[reveman, 2015/05/20 14:26:07]

Please pass the type as a parameter to this helper function instead of calling
::GetSupportedTypes twice.

[danakj, 2015/05/20 17:51:14]

Done.

   DCHECK(!supported_types.empty());