Add PERSISTENT_MAP usage for GpuMemoryBuffers.

content/browser/gpu/browser_gpu_channel_host_factory.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 "content/browser/gpu/browser_gpu_channel_host_factory.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/profiler/scoped_tracker.h"
@@ skipping 236 matching lines @@
   g_enabled_gpu_memory_buffer_usages.Get().insert(usage);
 }
 
 // static
 bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferFactoryUsageEnabled(
     gfx::GpuMemoryBuffer::Usage usage) {
   return g_enabled_gpu_memory_buffer_usages.Get().count(usage) != 0;
 }
 
 // static
-uint32 BrowserGpuChannelHostFactory::GetImageTextureTarget() {
-  if (!IsGpuMemoryBufferFactoryUsageEnabled(gfx::GpuMemoryBuffer::MAP))
+uint32 BrowserGpuChannelHostFactory::GetImageTextureTarget(
+    gfx::GpuMemoryBuffer::Usage usage) {
+  if (!IsGpuMemoryBufferFactoryUsageEnabled(usage))
     return GL_TEXTURE_2D;
 
   std::vector<gfx::GpuMemoryBufferType> supported_types;
-  GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);
+  GpuMemoryBufferFactory::GetSupportedTypes(usage, &supported_types);

[reveman, 2015/05/19 16:12:12]

Instead of changing GetSupportedTypes (which might be removed soon) I think we
should use IsGpuMemoryBufferConfigurationSupported here to determine what type
is actually going to be used.

Requires adding gfx::GpuMemoryBuffer::Format as the first param to this function
but I think that's what we want. It will return the target to use for a specific
combination of format and usage.

[danakj, 2015/05/19 20:11:52]

I don't understand this request :(

IsGpuMemoryBufferConfigurationSupported(format, usage) returns true if a
format,usage pair is valid. It doesn't take a type as a parameter. Is that what
you are asking for?

The IsGpuMemoryBufferConfigurationSupported() method has no comments explaining
what it is doing so I'm not sure TBH. But for SHARED_MEMORY type it always
returns false. So then how would GetImageTextureTarget decided we're going to
use SHARED_MEMORY ever?

[danakj, 2015/05/19 22:19:43]

OK thanks for the discussion about this! I've passed format to this method
(hardcoded at the callsites with TODOs) and am using a static
IsGMBConfigSupported method to decide to use native or shared memory buffers.

   DCHECK(!supported_types.empty());
 
   // The GPU service will always use the preferred type.
   gfx::GpuMemoryBufferType type = supported_types[0];
 
   switch (type) {
     case gfx::SURFACE_TEXTURE_BUFFER:
     case gfx::OZONE_NATIVE_BUFFER:
       // GPU memory buffers that are shared with the GL using EGLImages require
       // TEXTURE_EXTERNAL_OES.
@@ skipping 193 matching lines @@
 
 bool BrowserGpuChannelHostFactory::IsGpuMemoryBufferConfigurationSupported(
     gfx::GpuMemoryBuffer::Format format,
     gfx::GpuMemoryBuffer::Usage usage) {
   // Return early if usage is not enabled.
   if (!IsGpuMemoryBufferFactoryUsageEnabled(usage))
     return false;
 
   // Preferred type is always used by factory.
   std::vector<gfx::GpuMemoryBufferType> supported_types;
-  GpuMemoryBufferFactory::GetSupportedTypes(&supported_types);
+  GpuMemoryBufferFactory::GetSupportedTypes(usage, &supported_types);
   DCHECK(!supported_types.empty());
   switch (supported_types[0]) {
     case gfx::SHARED_MEMORY_BUFFER:
       // Shared memory buffers must be created in-process.
       return false;
 #if defined(OS_MACOSX)
     case gfx::IO_SURFACE_BUFFER:
       return GpuMemoryBufferFactoryIOSurface::
           IsGpuMemoryBufferConfigurationSupported(format, usage);
 #endif
@@ skipping 71 matching lines @@
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   CreateGpuMemoryBufferCallbackMap::iterator iter =
       create_gpu_memory_buffer_requests_.find(request_id);
   DCHECK(iter != create_gpu_memory_buffer_requests_.end());
   iter->second.Run(handle);
   create_gpu_memory_buffer_requests_.erase(iter);
 }
 
 }  // namespace content