Saner fallback path when RasterBuffer failed to create a GPU resource

Currently, in particular on Mac, CreateGpuMemoryBuffer can fail, in which case
we can't rasterize the corresponding tile in ZeroCopyRasterBufferImpl, and we
just create a GL texture without binding anything to it, which ends up showing
black when we display. This is somewhat problematic to emulate with SharedImage
where it is not a valid state (SharedImages must have well-defined dimensions
and format).
Instead, we handle the failure by not creating a texture at all, keeping a zero
mailbox, and falling back to OOM rendering mode (checkerboarding) for the
corresponding tile.

Bug: 882513, 554541
Change-Id: Iffd29a660f655c2dee8179fd90baa2a15ae42bf7
Reviewed-on: https://chromium-review.googlesource.com/c/1303393
Commit-Queue: Antoine Labour <piman@chromium.org>
Reviewed-by: Eric Karl <ericrk@chromium.org>
Cr-Commit-Position: refs/heads/master@{#603661}

diff --git a/cc/raster/zero_copy_raster_buffer_provider.cc b/cc/raster/zero_copy_raster_buffer_provider.cc
index 7007959..bde805a 100644
--- a/cc/raster/zero_copy_raster_buffer_provider.cc
+++ b/cc/raster/zero_copy_raster_buffer_provider.cc

@@ -81,6 +81,14 @@
         gpu_memory_buffer_(std::move(backing_->gpu_memory_buffer)) {}
 
   ~ZeroCopyRasterBufferImpl() override {
+    // If GpuMemoryBuffer allocation failed (https://crbug.com/554541), then
+    // we don't have anything to give to the display compositor, so we report a
+    // zero mailbox that will result in checkerboarding.
+    if (!gpu_memory_buffer_) {
+      DCHECK(backing_->mailbox.IsZero());
+      return;
+    }
+
     // This is destroyed on the compositor thread when raster is complete, but
     // before the backing is prepared for export to the display compositor. So
     // we can set up the texture and SyncToken here.
@@ -125,19 +133,10 @@
     }
 
     if (!backing_->image_id) {
-      // If GpuMemoryBuffer allocation failed (https://crbug.com/554541), then
-      // we don't have anything to give to the display compositor, but also no
-      // way to report an error, so we just make a texture but don't bind
-      // anything to it. Many blink layout tests on macOS fail to have no
-      // |gpu_memory_buffer_| here, so any error reporting will spam console
-      // logs (https://crbug.com/871031).
-      if (gpu_memory_buffer_) {
-        backing_->image_id = gl->CreateImageCHROMIUM(
-            gpu_memory_buffer_->AsClientBuffer(), resource_size_.width(),
-            resource_size_.height(), viz::GLInternalFormat(resource_format_));
-        gl->BindTexImage2DCHROMIUM(backing_->texture_target,
-                                   backing_->image_id);
-      }
+      backing_->image_id = gl->CreateImageCHROMIUM(
+          gpu_memory_buffer_->AsClientBuffer(), resource_size_.width(),
+          resource_size_.height(), viz::GLInternalFormat(resource_format_));
+      gl->BindTexImage2DCHROMIUM(backing_->texture_target, backing_->image_id);
     } else {
       gl->ReleaseTexImage2DCHROMIUM(backing_->texture_target,
                                     backing_->image_id);