Don't forbid GPU process if WebGL/WebGL2 is disabled on GPU but not browser.

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 <algorithm>
+#include <iterator>
 #include <memory>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/metrics/sparse_histogram.h"
 #include "base/strings/string_number_conversions.h"
@@ skipping 323 matching lines @@
       if (command_line->HasSwitch(switches::kDisableGpu))
         *reason += "through commandline switch --disable-gpu.";
       else
         *reason += "in chrome://settings.";
     }
     return false;
   }
 
   // We only need to block GPU process if more features are disallowed other
   // than those in the preliminary gpu feature flags because the latter work
-  // through renderer commandline switches.
-  std::set<int> features = preliminary_blacklisted_features_;
-  gpu::MergeFeatureSets(&features, blacklisted_features_);
-  if (features.size() > preliminary_blacklisted_features_.size()) {
+  // through renderer commandline switches. WebGL and WebGL2 should not matter
+  // because their context creation can always be rejected on the GPU process
+  // side.

[Ken Russell (switch to Gerrit), 2016/11/15 01:25:14]

Would other GPU acceleration features also be good candidates for this handling?
If so should we add a TODO about re-evaluating them?

[Zhenyao Mo, 2016/11/15 01:38:21]

Might be.  Good point. Added.

+  std::set<int> feature_diffs;
+  std::set_difference(blacklisted_features_.begin(),
+                      blacklisted_features_.end(),
+                      preliminary_blacklisted_features_.begin(),
+                      preliminary_blacklisted_features_.end(),
+                      std::inserter(feature_diffs, feature_diffs.begin()));
+  if (feature_diffs.size()) {
+    feature_diffs.erase(gpu::GPU_FEATURE_TYPE_WEBGL);
+    feature_diffs.erase(gpu::GPU_FEATURE_TYPE_WEBGL2);
+  }
+  if (feature_diffs.size()) {
     if (reason) {
-      *reason = "Features are disabled upon full but not preliminary GPU info.";
+      *reason = "Features are disabled on full but not preliminary GPU info.";
     }
     return false;
   }
 
   if (blacklisted_features_.size() == gpu::NUMBER_OF_GPU_FEATURE_TYPES) {
     // On Linux, we use cached GL strings to make blacklist decsions at browser
     // startup time. We need to launch the GPU process to validate these
     // strings even if all features are blacklisted. If all GPU features are
     // disabled, the GPU process will only initialize GL bindings, create a GL
     // context, and collect full GPU info.
@@ skipping 942 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