cc: Add mailbox support to ResourceProvider write locks.

cc/resources/resource_provider.cc

 // Copyright 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 "cc/resources/resource_provider.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <algorithm>
@@ skipping 677 matching lines @@
     return;
   } else {
     DeleteResourceInternal(it, NORMAL);
   }
 }
 
 void ResourceProvider::DeleteResourceInternal(ResourceMap::iterator it,
                                               DeleteStyle style) {
   TRACE_EVENT0("cc", "ResourceProvider::DeleteResourceInternal");
   Resource* resource = &it->second;
-  bool lost_resource = resource->lost;
+  DCHECK(resource->exported_count == 0 || style != NORMAL);
 
-  DCHECK(resource->exported_count == 0 || style != NORMAL);
-  if (style == FOR_SHUTDOWN && resource->exported_count > 0)
-    lost_resource = true;
+  bool lost_resource =
+      resource->lost ||
+      (style == FOR_SHUTDOWN && resource->exported_count > 0) ||
+      (IsGpuResourceType(resource->type) && lost_output_surface_);
+
+  if (!lost_resource &&
+      resource->synchronization_state() == Resource::NEEDS_WAIT) {
+    DCHECK(resource->allocated);
+    DCHECK(IsGpuResourceType(resource->type));
+    GLES2Interface* gl = ContextGL();
+    DCHECK(gl);
+    resource->WaitSyncToken(gl);
+  }
 
   if (resource->image_id) {
     DCHECK(resource->origin == Resource::INTERNAL);
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
     gl->DestroyImageCHROMIUM(resource->image_id);
   }
   if (resource->gl_upload_query_id) {
     DCHECK(resource->origin == Resource::INTERNAL);
     GLES2Interface* gl = ContextGL();
@@ skipping 10 matching lines @@
     DCHECK(resource->origin == Resource::INTERNAL);
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
     gl->DeleteBuffers(1, &resource->gl_pixel_buffer_id);
   }
   if (resource->origin == Resource::EXTERNAL) {
     DCHECK(resource->mailbox().IsValid());
     gpu::SyncToken sync_token = resource->mailbox().sync_token();
     if (IsGpuResourceType(resource->type)) {
       DCHECK(resource->mailbox().IsTexture());
-      lost_resource |= lost_output_surface_;
       GLES2Interface* gl = ContextGL();
       DCHECK(gl);
       if (resource->gl_id) {
         gl->DeleteTextures(1, &resource->gl_id);
         resource->gl_id = 0;
         if (!lost_resource) {
           const GLuint64 fence_sync = gl->InsertFenceSyncCHROMIUM();
           gl->ShallowFlushCHROMIUM();
           gl->GenSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
         }
@@ skipping 65 matching lines @@
     DCHECK(resource->allocated);
     DCHECK_EQ(RGBA_8888, resource->format);
     SkImageInfo source_info =
         SkImageInfo::MakeN32Premul(image_size.width(), image_size.height());
     size_t image_stride = image_size.width() * 4;
 
     ScopedWriteLockSoftware lock(this, id);
     SkCanvas dest(lock.sk_bitmap());
     dest.writePixels(source_info, image, image_stride, 0, 0);
   } else {
-    ScopedWriteLockGL lock(this, id);
-    DCHECK(lock.texture_id());
+    ScopedWriteLockGL lock(this, id, false);
+    unsigned resource_texture_id = lock.texture_id();
+    DCHECK(resource_texture_id);
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
-    gl->BindTexture(resource->target, lock.texture_id());
+    gl->BindTexture(resource->target, resource_texture_id);
     if (resource->format == ETC1) {
       DCHECK_EQ(resource->target, static_cast<GLenum>(GL_TEXTURE_2D));
       int image_bytes = ResourceUtil::CheckedSizeInBytes<int>(image_size, ETC1);
       gl->CompressedTexImage2D(resource->target, 0, GLInternalFormat(ETC1),
                                image_size.width(), image_size.height(), 0,
                                image_bytes, image);
     } else {
       gl->TexSubImage2D(resource->target, 0, 0, 0, image_size.width(),
                         image_size.height(), GLDataFormat(resource->format),
                         GLDataType(resource->format), image);
     }
     const uint64_t fence_sync = gl->InsertFenceSyncCHROMIUM();
     gl->OrderingBarrierCHROMIUM();
     gpu::SyncToken sync_token;
     gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, sync_token.GetData());
-    lock.UpdateResourceSyncToken(sync_token);
+    lock.set_sync_token(sync_token);
   }
 }
 
 void ResourceProvider::GenerateSyncTokenForResource(ResourceId resource_id) {
   Resource* resource = GetResource(resource_id);
   if (!resource->needs_sync_token())
     return;
 
   gpu::SyncToken sync_token;
   GLES2Interface* gl = ContextGL();
@@ skipping 50 matching lines @@
     bool create_gpu_memory_buffer) {
   Resource* resource = GetResource(id);
   DCHECK(!resource->locked_for_write) << "locked for write: "
                                       << resource->locked_for_write;
   DCHECK_EQ(resource->exported_count, 0);
   // Uninitialized! Call SetPixels or LockForWrite first.
   DCHECK(resource->allocated);
 
   // Mailbox sync_tokens must be processed by a call to
   // WaitSyncTokenIfNeeded() prior to calling LockForRead().
-  DCHECK_NE(Resource::NEEDS_WAIT, resource->synchronization_state());
+  // DCHECK_NE(Resource::NEEDS_WAIT, resource->synchronization_state());

[piman, 2016/06/10 22:57:01]

nit: I think you should leave this (and remove the wait).

This is used on the browser compositor, in the parent, and we do want to make
sure we correctly synchronized in GLRenderer::BeginDrawingFrame, because
otherwise we could cause a context switch in the middle of drawing, which has
very bad performance on mobile.

[sunnyps, 2016/06/11 01:29:52]

Done.

+
+  WaitSyncTokenIfNeeded(id);
 
   LazyCreate(resource);
 
   if (IsGpuResourceType(resource->type) && !resource->gl_id) {
     DCHECK(resource->origin != Resource::INTERNAL);
     DCHECK(resource->mailbox().IsTexture());
 
     GLES2Interface* gl = ContextGL();
     DCHECK(gl);
     resource->gl_id = gl->CreateAndConsumeTextureCHROMIUM(
@@ skipping 54 matching lines @@
       ResourceIdArray unused;
       unused.push_back(id);
       DeleteAndReturnUnusedResourcesToChild(child_it, NORMAL, unused);
     }
   }
 }
 
 ResourceProvider::Resource* ResourceProvider::LockForWrite(ResourceId id) {
   Resource* resource = GetResource(id);
   DCHECK(CanLockForWrite(id));
-  DCHECK_NE(Resource::NEEDS_WAIT, resource->synchronization_state());
+  // DCHECK_NE(Resource::NEEDS_WAIT, resource->synchronization_state());

[piman, 2016/06/10 22:57:01]

nit: remove

[sunnyps, 2016/06/11 01:29:52]

Done.

+  if (resource->allocated)
+    WaitSyncTokenIfNeeded(id);
   resource->locked_for_write = true;
   resource->SetLocallyUsed();
   return resource;
 }
 
 bool ResourceProvider::CanLockForWrite(ResourceId id) {
   Resource* resource = GetResource(id);
   return !resource->locked_for_write && !resource->lock_for_read_count &&
          !resource->exported_count && resource->origin == Resource::INTERNAL &&
          !resource->lost && ReadLockFenceHasPassed(resource);
 }
 
 bool ResourceProvider::IsOverlayCandidate(ResourceId id) {
   Resource* resource = GetResource(id);
   return resource->is_overlay_candidate;
 }
 
-void ResourceProvider::UnlockForWrite(ResourceProvider::Resource* resource) {
+void ResourceProvider::UnlockForWrite(Resource* resource) {
   DCHECK(resource->locked_for_write);
   DCHECK_EQ(resource->exported_count, 0);
   DCHECK(resource->origin == Resource::INTERNAL);
   resource->locked_for_write = false;
-  resource->SetSynchronized();
+  // resource->SetSynchronized();

[piman, 2016/06/10 22:57:01]

nit: remove.

[sunnyps, 2016/06/11 01:29:52]

Done.

 }
 
 void ResourceProvider::EnableReadLockFencesForTesting(ResourceId id) {
   Resource* resource = GetResource(id);
   DCHECK(resource);
   resource->read_lock_fences_enabled = true;
 }
 
 ResourceProvider::ScopedReadLockGL::ScopedReadLockGL(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_id_(resource_id),
-      resource_(resource_provider->LockForRead(resource_id, false)) {
-  DCHECK(resource_);
+    : resource_provider_(resource_provider), resource_id_(resource_id) {
+  const Resource* resource = resource_provider->LockForRead(resource_id, false);
+  texture_id_ = resource->gl_id;
+  target_ = resource->target;
+  size_ = resource->size;
 }
 
 ResourceProvider::ScopedReadLockGL::~ScopedReadLockGL() {
   resource_provider_->UnlockForRead(resource_id_);
 }
 
 ResourceProvider::ScopedSamplerGL::ScopedSamplerGL(
     ResourceProvider* resource_provider,
     ResourceId resource_id,
     GLenum filter)
-    : ScopedReadLockGL(resource_provider, resource_id),
+    : resource_lock_(resource_provider, resource_id),
       unit_(GL_TEXTURE0),
-      target_(resource_provider->BindForSampling(resource_id, unit_, filter)) {
-}
+      target_(resource_provider->BindForSampling(resource_id, unit_, filter)) {}
 
 ResourceProvider::ScopedSamplerGL::ScopedSamplerGL(
     ResourceProvider* resource_provider,
     ResourceId resource_id,
     GLenum unit,
     GLenum filter)
-    : ScopedReadLockGL(resource_provider, resource_id),
+    : resource_lock_(resource_provider, resource_id),
       unit_(unit),
-      target_(resource_provider->BindForSampling(resource_id, unit_, filter)) {
-}
+      target_(resource_provider->BindForSampling(resource_id, unit_, filter)) {}
 
 ResourceProvider::ScopedSamplerGL::~ScopedSamplerGL() {
 }
 
 ResourceProvider::ScopedWriteLockGL::ScopedWriteLockGL(
     ResourceProvider* resource_provider,
-    ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_(resource_provider->LockForWrite(resource_id)),
-      texture_id_(0),
-      set_sync_token_(false) {
-  resource_provider_->LazyAllocate(resource_);
-  texture_id_ = resource_->gl_id;
-  DCHECK(texture_id_);
-  if (resource_->image_id && resource_->dirty_image)
-    resource_provider_->BindImageForSampling(resource_);
+    ResourceId resource_id,
+    bool create_mailbox)
+    : resource_provider_(resource_provider), resource_id_(resource_id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  Resource* resource = resource_provider->LockForWrite(resource_id);
+  resource_provider_->LazyAllocate(resource);
+  if (resource->image_id && resource->dirty_image)
+    resource_provider_->BindImageForSampling(resource);
+  if (create_mailbox) {
+    resource_provider_->CreateMailboxAndBindResource(
+        resource_provider_->ContextGL(), resource);
+  }
+  texture_id_ = resource->gl_id;
+  target_ = resource->target;
+  format_ = resource->format;
+  size_ = resource->size;
+  mailbox_ = resource->mailbox();
 }
 
 ResourceProvider::ScopedWriteLockGL::~ScopedWriteLockGL() {
-  if (set_sync_token_)
-    resource_->UpdateSyncToken(sync_token_);
-  resource_provider_->UnlockForWrite(resource_);
+  DCHECK(thread_checker_.CalledOnValidThread());
+  Resource* resource = resource_provider_->GetResource(resource_id_);
+  DCHECK(resource->locked_for_write);
+  if (sync_token_.HasData())
+    resource->UpdateSyncToken(sync_token_);
+  resource_provider_->UnlockForWrite(resource);
+}
+
+ResourceProvider::ScopedTextureProvider::ScopedTextureProvider(
+    gpu::gles2::GLES2Interface* gl,
+    ScopedWriteLockGL* resource_lock,
+    bool use_mailbox)
+    : gl_(gl), use_mailbox_(use_mailbox) {
+  if (use_mailbox_) {
+    texture_id_ = gl_->CreateAndConsumeTextureCHROMIUM(
+        resource_lock->target(), resource_lock->mailbox().name());
+  } else {
+    texture_id_ = resource_lock->texture_id();
+  }
+  DCHECK(texture_id_);
+}
+
+ResourceProvider::ScopedTextureProvider::~ScopedTextureProvider() {
+  if (use_mailbox_)
+    gl_->DeleteTextures(1, &texture_id_);
+}
+
+ResourceProvider::ScopedSkSurfaceProvider::ScopedSkSurfaceProvider(
+    ContextProvider* context_provider,
+    ScopedWriteLockGL* resource_lock,
+    bool use_mailbox,
+    bool use_distance_field_text,
+    bool can_use_lcd_text,
+    int msaa_sample_count)
+    : texture_provider_(context_provider->ContextGL(),
+                        resource_lock,
+                        use_mailbox) {
+  GrGLTextureInfo texture_info;
+  texture_info.fID = texture_provider_.texture_id();
+  texture_info.fTarget = resource_lock->target();
+  GrBackendTextureDesc desc;
+  desc.fFlags = kRenderTarget_GrBackendTextureFlag;
+  desc.fWidth = resource_lock->size().width();
+  desc.fHeight = resource_lock->size().height();
+  desc.fConfig = ToGrPixelConfig(resource_lock->format());
+  desc.fOrigin = kTopLeft_GrSurfaceOrigin;
+  desc.fTextureHandle = skia::GrGLTextureInfoToGrBackendObject(texture_info);
+  desc.fSampleCnt = msaa_sample_count;
+
+  uint32_t flags =
+      use_distance_field_text ? SkSurfaceProps::kUseDistanceFieldFonts_Flag : 0;
+  // Use unknown pixel geometry to disable LCD text.
+  SkSurfaceProps surface_props(flags, kUnknown_SkPixelGeometry);
+  if (can_use_lcd_text) {
+    // LegacyFontHost will get LCD text and skia figures out what type to use.
+    surface_props =
+        SkSurfaceProps(flags, SkSurfaceProps::kLegacyFontHost_InitType);
+  }
+  sk_surface_ = SkSurface::MakeFromBackendTextureAsRenderTarget(
+      context_provider->GrContext(), desc, &surface_props);
+}
+
+ResourceProvider::ScopedSkSurfaceProvider::~ScopedSkSurfaceProvider() {
+  if (sk_surface_.get()) {
+    sk_surface_->prepareForExternalIO();
+    sk_surface_.reset();
+  }
 }
 
 void ResourceProvider::PopulateSkBitmapWithResource(
     SkBitmap* sk_bitmap, const Resource* resource) {
   DCHECK_EQ(RGBA_8888, resource->format);
   SkImageInfo info = SkImageInfo::MakeN32Premul(resource->size.width(),
                                                 resource->size.height());
   sk_bitmap->installPixels(info, resource->pixels, info.minRowBytes());
 }
 
 ResourceProvider::ScopedReadLockSoftware::ScopedReadLockSoftware(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
     : resource_provider_(resource_provider), resource_id_(resource_id) {
   const Resource* resource = resource_provider->LockForRead(resource_id, false);
   ResourceProvider::PopulateSkBitmapWithResource(&sk_bitmap_, resource);
 }
 
 ResourceProvider::ScopedReadLockSoftware::~ScopedReadLockSoftware() {
   resource_provider_->UnlockForRead(resource_id_);
 }
 
 ResourceProvider::ScopedWriteLockSoftware::ScopedWriteLockSoftware(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_(resource_provider->LockForWrite(resource_id)) {
-  ResourceProvider::PopulateSkBitmapWithResource(&sk_bitmap_, resource_);
+    : resource_provider_(resource_provider), resource_id_(resource_id) {
+  ResourceProvider::PopulateSkBitmapWithResource(
+      &sk_bitmap_, resource_provider->LockForWrite(resource_id));
   DCHECK(valid());
 }
 
 ResourceProvider::ScopedWriteLockSoftware::~ScopedWriteLockSoftware() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  resource_provider_->UnlockForWrite(resource_);
+  resource_provider_->UnlockForWrite(
+      resource_provider_->GetResource(resource_id_));
 }
 
 ResourceProvider::ScopedWriteLockGpuMemoryBuffer::
     ScopedWriteLockGpuMemoryBuffer(ResourceProvider* resource_provider,
                                    ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_(resource_provider->LockForWrite(resource_id)) {
-  DCHECK(IsGpuResourceType(resource_->type));
-  gpu_memory_buffer_ = std::move(resource_->gpu_memory_buffer);
-  resource_->gpu_memory_buffer = nullptr;
+    : resource_provider_(resource_provider), resource_id_(resource_id) {
+  Resource* resource = resource_provider->LockForWrite(resource_id);
+  DCHECK(IsGpuResourceType(resource->type));
+  format_ = resource->format;
+  size_ = resource->size;
+  gpu_memory_buffer_ = std::move(resource->gpu_memory_buffer);
+  resource->gpu_memory_buffer = nullptr;
 }
 
 ResourceProvider::ScopedWriteLockGpuMemoryBuffer::
     ~ScopedWriteLockGpuMemoryBuffer() {
   DCHECK(thread_checker_.CalledOnValidThread());
-  resource_provider_->UnlockForWrite(resource_);
-  if (!gpu_memory_buffer_)
-    return;
-
-  DCHECK(!resource_->gpu_memory_buffer);
-  resource_provider_->LazyCreate(resource_);
-  resource_->gpu_memory_buffer = std::move(gpu_memory_buffer_);
-  if (resource_->gpu_memory_buffer)
-    resource_->gpu_memory_buffer_id = resource_->gpu_memory_buffer->GetId();
-  resource_->allocated = true;
-  resource_provider_->LazyCreateImage(resource_);
-  resource_->dirty_image = true;
-  resource_->is_overlay_candidate = true;
-  resource_->SetSynchronized();
-
-  // GpuMemoryBuffer provides direct access to the memory used by the GPU.
-  // Read lock fences are required to ensure that we're not trying to map a
-  // buffer that is currently in-use by the GPU.
-  resource_->read_lock_fences_enabled = true;
+  Resource* resource = resource_provider_->GetResource(resource_id_);
+  if (gpu_memory_buffer_) {
+    DCHECK(!resource->gpu_memory_buffer);
+    resource_provider_->LazyCreate(resource);
+    resource->gpu_memory_buffer = std::move(gpu_memory_buffer_);
+    if (resource->gpu_memory_buffer)
+      resource->gpu_memory_buffer_id = resource->gpu_memory_buffer->GetId();
+    resource->allocated = true;
+    resource_provider_->LazyCreateImage(resource);
+    resource->dirty_image = true;
+    resource->is_overlay_candidate = true;
+    // GpuMemoryBuffer provides direct access to the memory used by the GPU.
+    // Read lock fences are required to ensure that we're not trying to map a
+    // buffer that is currently in-use by the GPU.
+    resource->read_lock_fences_enabled = true;
+  }
+  resource_provider_->UnlockForWrite(resource);
 }
 
 gfx::GpuMemoryBuffer*
 ResourceProvider::ScopedWriteLockGpuMemoryBuffer::GetGpuMemoryBuffer() {
   if (!gpu_memory_buffer_) {
     gpu_memory_buffer_ =
         resource_provider_->gpu_memory_buffer_manager_->AllocateGpuMemoryBuffer(
-            resource_->size, BufferFormat(resource_->format),
+            size_, BufferFormat(format_),
             gfx::BufferUsage::GPU_READ_CPU_READ_WRITE, gpu::kNullSurfaceHandle);
   }
   return gpu_memory_buffer_.get();
 }
 
 ResourceProvider::ScopedReadLockGpuMemoryBuffer::ScopedReadLockGpuMemoryBuffer(
     ResourceProvider* resource_provider,
     ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_id_(resource_id),
-      resource_(resource_provider->LockForRead(resource_id, true)) {}
+    : resource_provider_(resource_provider), resource_id_(resource_id) {
+  const Resource* resource = resource_provider->LockForRead(resource_id, true);
+  gpu_memory_buffer_ = resource->gpu_memory_buffer.get();
+  texture_id_ = resource->gl_id;
+}
 
 ResourceProvider::ScopedReadLockGpuMemoryBuffer::
     ~ScopedReadLockGpuMemoryBuffer() {
   DCHECK(thread_checker_.CalledOnValidThread());
   resource_provider_->UnlockForRead(resource_id_);
 }
 
-gfx::GpuMemoryBuffer*
-ResourceProvider::ScopedReadLockGpuMemoryBuffer::GetGpuMemoryBuffer() const {
-  return resource_->gpu_memory_buffer.get();
-}
-
-unsigned ResourceProvider::ScopedReadLockGpuMemoryBuffer::GetTextureId() const {
-  return resource_->gl_id;
-}
-
-ResourceId ResourceProvider::ScopedReadLockGpuMemoryBuffer::GetResourceId()
-    const {
-  return resource_id_;
-}
-
-ResourceProvider::ScopedWriteLockGr::ScopedWriteLockGr(
-    ResourceProvider* resource_provider,
-    ResourceId resource_id)
-    : resource_provider_(resource_provider),
-      resource_(resource_provider->LockForWrite(resource_id)),
-      set_sync_token_(false) {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  resource_provider_->LazyAllocate(resource_);
-  if (resource_->image_id && resource_->dirty_image)
-    resource_provider_->BindImageForSampling(resource_);
-}
-
-ResourceProvider::ScopedWriteLockGr::~ScopedWriteLockGr() {
-  DCHECK(thread_checker_.CalledOnValidThread());
-  DCHECK(resource_->locked_for_write);
-  if (set_sync_token_)
-    resource_->UpdateSyncToken(sync_token_);
-
-  resource_provider_->UnlockForWrite(resource_);
-}
-
-void ResourceProvider::ScopedWriteLockGr::InitSkSurface(
-    GrContext* gr_context,
-    bool use_distance_field_text,
-    bool can_use_lcd_text,
-    int msaa_sample_count) {
-  DCHECK(resource_->locked_for_write);
-
-  GrGLTextureInfo texture_info;
-  texture_info.fID = resource_->gl_id;
-  texture_info.fTarget = resource_->target;
-  GrBackendTextureDesc desc;
-  desc.fFlags = kRenderTarget_GrBackendTextureFlag;
-  desc.fWidth = resource_->size.width();
-  desc.fHeight = resource_->size.height();
-  desc.fConfig = ToGrPixelConfig(resource_->format);
-  desc.fOrigin = kTopLeft_GrSurfaceOrigin;
-  desc.fTextureHandle = skia::GrGLTextureInfoToGrBackendObject(texture_info);
-  desc.fSampleCnt = msaa_sample_count;
-
-  uint32_t flags =
-      use_distance_field_text ? SkSurfaceProps::kUseDistanceFieldFonts_Flag : 0;
-  // Use unknown pixel geometry to disable LCD text.
-  SkSurfaceProps surface_props(flags, kUnknown_SkPixelGeometry);
-  if (can_use_lcd_text) {
-    // LegacyFontHost will get LCD text and skia figures out what type to use.
-    surface_props =
-        SkSurfaceProps(flags, SkSurfaceProps::kLegacyFontHost_InitType);
-  }
-  sk_surface_ = SkSurface::MakeFromBackendTextureAsRenderTarget(
-      gr_context, desc, &surface_props);
-}
-
-void ResourceProvider::ScopedWriteLockGr::ReleaseSkSurface() {
-  DCHECK(sk_surface_);
-  sk_surface_->prepareForExternalIO();
-  sk_surface_.reset();
-}
-
 ResourceProvider::SynchronousFence::SynchronousFence(
     gpu::gles2::GLES2Interface* gl)
     : gl_(gl), has_synchronized_(true) {
 }
 
 ResourceProvider::SynchronousFence::~SynchronousFence() {
 }
 
 void ResourceProvider::SynchronousFence::Set() {
   has_synchronized_ = false;
@@ skipping 119 matching lines @@
       gl->OrderingBarrierCHROMIUM();
       gl->GenUnverifiedSyncTokenCHROMIUM(fence_sync, new_sync_token.GetData());
       unverified_sync_tokens.push_back(new_sync_token.GetData());
     }
 
     if (!unverified_sync_tokens.empty()) {
       gl->VerifySyncTokensCHROMIUM(unverified_sync_tokens.data(),
                                    unverified_sync_tokens.size());
     }
   }
-  for (Resource* resource : need_synchronization_resources) {
+  for (Resource* resource : need_synchronization_resources)
     resource->UpdateSyncToken(new_sync_token);
-    resource->SetSynchronized();
-  }
 
   // Transfer Resources
   DCHECK_EQ(resources.size(), resource_ids.size());
   for (size_t i = 0; i < resources.size(); ++i) {
     Resource* source = resources[i];
     const ResourceId id = resource_ids[i];
 
     DCHECK(!delegated_sync_points_required_ || !source->needs_sync_token());
     DCHECK(!delegated_sync_points_required_ ||
            Resource::LOCALLY_USED != source->synchronization_state());
 
     TransferableResource resource;
     TransferResource(source, id, &resource);
 
+    source->SetSynchronized();

[piman, 2016/06/10 22:57:01]

Is this right?
If a resource comes from the raster thread, we would have generated the sync
token on the worker context, but nothing here would wait for it on the
compositor thread, so I don't think it's right to SetSynchronized here. It's
valid to do on the need_synchronization_resources ones, because they were
created on the compositor context, and we just generated a token for them.

[sunnyps, 2016/06/11 01:29:52]

Done.

     source->exported_count++;
     list->push_back(resource);
   }
 }
 
 void ResourceProvider::ReceiveFromChild(
     int child, const TransferableResourceArray& resources) {
   DCHECK(thread_checker_.CalledOnValidThread());
   GLES2Interface* gl = ContextGL();
   Child& child_info = children_.find(child)->second;
@@ skipping 379 matching lines @@
   if (resource->type == RESOURCE_TYPE_GPU_MEMORY_BUFFER) {
     resource->gpu_memory_buffer =
         gpu_memory_buffer_manager_->AllocateGpuMemoryBuffer(
             size, BufferFormat(format),
             gfx::BufferUsage::GPU_READ_CPU_READ_WRITE, gpu::kNullSurfaceHandle);
     if (resource->gpu_memory_buffer)
       resource->gpu_memory_buffer_id = resource->gpu_memory_buffer->GetId();
     LazyCreateImage(resource);
     resource->dirty_image = true;
     resource->is_overlay_candidate = true;
+    // GpuMemoryBuffer provides direct access to the memory used by the GPU.
+    // Read lock fences are required to ensure that we're not trying to map a
+    // buffer that is currently in-use by the GPU.
+    resource->read_lock_fences_enabled = true;
   } else if (use_texture_storage_ext_ &&
              IsFormatSupportedForStorage(format, use_texture_format_bgra_) &&
              (resource->hint & TEXTURE_HINT_IMMUTABLE)) {
     GLenum storage_format = TextureToStorageFormat(format);
     gl->TexStorage2DEXT(resource->target, 1, storage_format, size.width(),
                         size.height());
   } else {
     // ETC1 does not support preallocation.
     if (format != ETC1) {
       gl->TexImage2D(resource->target, 0, GLInternalFormat(format),
@@ skipping 156 matching lines @@
 
     const int kImportance = 2;
     pmd->CreateSharedGlobalAllocatorDump(guid);
     pmd->AddOwnershipEdge(dump->guid(), guid, kImportance);
   }
 
   return true;
 }
 
 }  // namespace cc