Avoid WTF::Vector::at() and operator[] in core/dom.

third_party/WebKit/Source/core/dom/FrameRequestCallbackCollection.cpp

 // 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 "core/dom/FrameRequestCallbackCollection.h"
 
 #include "core/dom/FrameRequestCallback.h"
 #include "core/frame/PerformanceMonitor.h"
 #include "core/inspector/InspectorInstrumentation.h"
 #include "core/inspector/InspectorTraceEvents.h"
@@ skipping 28 matching lines @@
       InspectorInstrumentation::asyncTaskCanceled(m_context, m_callbacks[i]);
       InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(
           m_context, "cancelAnimationFrame", true);
       m_callbacks.remove(i);
       TRACE_EVENT_INSTANT1("devtools.timeline", "CancelAnimationFrame",
                            TRACE_EVENT_SCOPE_THREAD, "data",
                            InspectorAnimationFrameEvent::data(m_context, id));
       return;
     }
   }
-  for (size_t i = 0; i < m_callbacksToInvoke.size(); ++i) {
-    if (m_callbacksToInvoke[i]->m_id == id) {
-      InspectorInstrumentation::asyncTaskCanceled(m_context,
-                                                  m_callbacksToInvoke[i]);
+  for (const auto& callback : m_callbacksToInvoke) {
+    if (callback->m_id == id) {
+      InspectorInstrumentation::asyncTaskCanceled(m_context, callback);
       InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(
           m_context, "cancelAnimationFrame", true);
       TRACE_EVENT_INSTANT1("devtools.timeline", "CancelAnimationFrame",
                            TRACE_EVENT_SCOPE_THREAD, "data",
                            InspectorAnimationFrameEvent::data(m_context, id));
-      m_callbacksToInvoke[i]->m_cancelled = true;
+      callback->m_cancelled = true;
       // will be removed at the end of executeCallbacks()
       return;
     }
   }
 }
 
 void FrameRequestCallbackCollection::executeCallbacks(
     double highResNowMs,
     double highResNowMsLegacy) {
   // First, generate a list of callbacks to consider.  Callbacks registered from
   // this point on are considered only for the "next" frame, not this one.
   DCHECK(m_callbacksToInvoke.isEmpty());
   m_callbacksToInvoke.swap(m_callbacks);
 
-  for (size_t i = 0; i < m_callbacksToInvoke.size(); ++i) {
-    FrameRequestCallback* callback = m_callbacksToInvoke[i].get();
+  for (const auto& callback : m_callbacksToInvoke) {
     if (!callback->m_cancelled) {
       TRACE_EVENT1(
           "devtools.timeline", "FireAnimationFrame", "data",
           InspectorAnimationFrameEvent::data(m_context, callback->m_id));
       InspectorInstrumentation::NativeBreakpoint nativeBreakpoint(
           m_context, "animationFrameFired", false);
       InspectorInstrumentation::AsyncTask asyncTask(m_context, callback);
       PerformanceMonitor::HandlerCall handlerCall(
           m_context, "requestAnimationFrame", true);
       if (callback->m_useLegacyTimeBase)
         callback->handleEvent(highResNowMsLegacy);
       else
         callback->handleEvent(highResNowMs);
       TRACE_EVENT_INSTANT1(TRACE_DISABLED_BY_DEFAULT("devtools.timeline"),
                            "UpdateCounters", TRACE_EVENT_SCOPE_THREAD, "data",
                            InspectorUpdateCountersEvent::data());
     }
   }
 
   m_callbacksToInvoke.clear();
 }
 
 DEFINE_TRACE(FrameRequestCallbackCollection) {
   visitor->trace(m_callbacks);
   visitor->trace(m_callbacksToInvoke);
   visitor->trace(m_context);
 }
 
 }  // namespace blink