Implement fallback from WMPI to WMPA.

content/browser/gpu/gpu_data_manager_impl_private.cc

 // Copyright (c) 2013 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/gpu_data_manager_impl_private.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
@@ skipping 915 matching lines @@
   const std::string group_name = base::FieldTrialList::FindFullName(
       "DisableAcceleratedVideoDecode");
   if (command_line->HasSwitch(switches::kDisableAcceleratedVideoDecode)) {
     // It was already disabled on the command line.
     return false;
   }
   if (IsFeatureBlacklisted(gpu::GPU_FEATURE_TYPE_ACCELERATED_VIDEO_DECODE))
     return true;
   if (group_name == "Disabled")
     return true;
+
+  // Accelerated decode is not available at all with --disable-gpu. It may be
+  // possible to eventually support --single-process and/or --in-process-gpu,
+  // but currently it fails long before trying because the supported profiles
+  // list isn't initialized. Setting the disable flag in these case is important
+  // for Android, as there is no fallback path if the renderer process chooses
+  // wrong.
+  if (command_line->HasSwitch(switches::kDisableGpu) ||

[DaleCurtis, 2016/01/06 21:03:22]

This is going to mean no webview support since they use --single-process AFAIK.
--in-process-gpu is used by Android One variants I think. Others? I don't think
these are reasonable restrictions, so if you want to land this now these need to
be marked with a TODO() fix and have a bug attached.

Why is this necessary at all? Won't we just fallback if possible during
initialize since the factories would be null in the gpu decoding case.

[sandersd (OOO until July 31), 2016/01/06 22:20:38]

I agree, but I don't think this is going to get fixed soon. TODO added.
No, by that time we already picked WMPI and it's too late.

+      command_line->HasSwitch(switches::kSingleProcess) ||
+      command_line->HasSwitch(switches::kInProcessGPU)) {
+    return true;
+  }
+
   return false;
 }
 
 void GpuDataManagerImplPrivate::GetDisabledExtensions(
     std::string* disabled_extensions) const {
   DCHECK(disabled_extensions);
   *disabled_extensions = disabled_extensions_;
 }
 
 void GpuDataManagerImplPrivate::BlockDomainFrom3DAPIs(
@@ skipping 280 matching lines @@
   gpu_info_.context_info_state = gpu::kCollectInfoFatalFailure;
 #if defined(OS_WIN)
   gpu_info_.dx_diagnostics_info_state = gpu::kCollectInfoFatalFailure;
 #endif
   complete_gpu_info_already_requested_ = true;
   // Some observers might be waiting.
   NotifyGpuInfoUpdate();
 }
 
 }  // namespace content