cc: Add more info to the BeginMainFrame dump.

cc/trees/proxy_impl.cc

 // Copyright 2015 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/trees/proxy_impl.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 214 matching lines @@
     *main_frame_will_happen = false;
   }
   completion->Signal();
 }
 
 // TODO(sunnyps): Remove this code once crbug.com/668892 is fixed.
 NOINLINE void ProxyImpl::DumpForBeginMainFrameHang() {
   DCHECK(IsImplThread());
   DCHECK(scheduler_);
 
-  char stack_string[20000] = "";
+  auto state = base::MakeUnique<base::trace_event::TracedValue>();
+
+  state->SetBoolean("commit_completion_waits_for_activation",
+                    commit_completion_waits_for_activation_);
+  state->SetBoolean("commit_completion_event", !!commit_completion_event_);
+  state->SetBoolean("activation_completion_event",
+                    !!activation_completion_event_);
+
+  state->BeginDictionary("scheduler_state");
+  scheduler_->AsValueInto(state.get());
+  state->EndDictionary();
+
+  state->BeginDictionary("tile_manager_state");
+  layer_tree_host_impl_->tile_manager()->ActivationStateAsValueInto(
+      state.get());
+  state->EndDictionary();
+
+  char stack_string[50000] = "";
   base::debug::Alias(&stack_string);
-
-  std::unique_ptr<base::trace_event::ConvertableToTraceFormat> scheduler_state =
-      scheduler_->AsValue();
-  strncat(stack_string, scheduler_state->ToString().c_str(),
-          arraysize(stack_string) - strlen(stack_string) - 1);
-
-  std::unique_ptr<base::trace_event::ConvertableToTraceFormat>
-      tile_manager_state =
-          layer_tree_host_impl_->tile_manager()->ActivationStateAsValue();
-  strncat(stack_string, tile_manager_state->ToString().c_str(),
-          arraysize(stack_string) - strlen(stack_string) - 1);
+  strncpy(stack_string, state->ToString().c_str(), arraysize(stack_string) - 1);
 
   base::debug::DumpWithoutCrashing();
 }
 
 void ProxyImpl::NotifyReadyToCommitOnImpl(
     CompletionEvent* completion,
     LayerTreeHost* layer_tree_host,
     base::TimeTicks main_thread_start_time,
     bool hold_commit_for_activation) {
   TRACE_EVENT0("cc", "ProxyImpl::NotifyReadyToCommitOnImpl");
@@ skipping 417 matching lines @@
 ProxyImpl::BlockedMainCommitOnly& ProxyImpl::blocked_main_commit() {
   DCHECK(IsMainThreadBlocked() && commit_completion_event_);
   return main_thread_blocked_commit_vars_unsafe_;
 }
 
 base::SingleThreadTaskRunner* ProxyImpl::MainThreadTaskRunner() {
   return task_runner_provider_->MainThreadTaskRunner();
 }
 
 }  // namespace cc