Fix devtools bugs Fix a spurious layout test failure

Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp

Index: Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp
diff --git a/Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp b/Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp
index 068625b7b55982d605e0d3db979ec93c65462689..acbeb9f76db78748e3a0d1924eae7fc203011214 100644
--- a/Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp
+++ b/Source/bindings/core/dart/DartInspectorDebuggerAgent.cpp
@@ -107,7 +107,6 @@ static String generateBreakpointIdDart(const String& scriptId, int lineNumber, i
 
 DartInspectorDebuggerAgent::DartInspectorDebuggerAgent(DartInjectedScriptManager* injectedScriptManager, InspectorDebuggerAgent* inspectorDebuggerAgent, InspectorPageAgent* pageAgent)
     : m_injectedScriptManager(injectedScriptManager)
-    , m_frontend(0)
     , m_pausedScriptState(nullptr)
     , m_currentCallStack(0)
     , m_javaScriptPauseScheduled(false)
@@ -178,7 +177,7 @@ void DartInspectorDebuggerAgent::enable(ErrorString*)
     enable();
     state()->setBoolean(DartDebuggerAgentState::debuggerEnabled, true);
 
-    ASSERT(m_frontend);
+    ASSERT(frontend());
 }
 
 void DartInspectorDebuggerAgent::disable(ErrorString*)
@@ -203,7 +202,7 @@ static PassOwnPtr<ScriptRegexp> compileSkipCallFramePattern(String patternText)
 void DartInspectorDebuggerAgent::restore()
 {
     if (enabled()) {
-        m_frontend->globalObjectCleared();
+        frontend()->globalObjectCleared();
         enable();
         long pauseState = state()->getLong(DartDebuggerAgentState::pauseOnExceptionsState);
         String error;
@@ -217,15 +216,14 @@ void DartInspectorDebuggerAgent::restore()
     }
 }
 
-void DartInspectorDebuggerAgent::setFrontend(InspectorFrontend* frontend)
+InspectorFrontend::Debugger* DartInspectorDebuggerAgent::frontend()
 {
-    m_frontend = InspectorFrontend::Debugger::from(frontend);
+    return m_inspectorDebuggerAgent->frontend();
 }
 
+
 void DartInspectorDebuggerAgent::clearFrontend()
 {
-    m_frontend = 0;
-
     if (!enabled())
         return;
 
@@ -872,10 +870,11 @@ void DartInspectorDebuggerAgent::didParseSource(const String& scriptId, const Sc
     String* sourceMapURLParam = sourceMapURL.isNull() ? 0 : &sourceMapURL;
 
     bool* hasSourceURLParam = hasSourceURL ? &hasSourceURL : 0;
+    ASSERT(frontend());
     if (!hasSyntaxError)
-        m_frontend->scriptParsed(scriptId, scriptURL, script.startLine, script.startColumn, script.endLine, script.endColumn, isContentScript, isInternalScript, sourceMapURLParam, hasSourceURLParam, languageParam, libraryIdParam);
+        frontend()->scriptParsed(scriptId, scriptURL, script.startLine, script.startColumn, script.endLine, script.endColumn, isContentScript, isInternalScript, sourceMapURLParam, hasSourceURLParam, languageParam, libraryIdParam);
     else
-        m_frontend->scriptFailedToParse(scriptId, scriptURL, script.startLine, script.startColumn, script.endLine, script.endColumn, isContentScript, isInternalScript, sourceMapURLParam, hasSourceURLParam, languageParam, libraryIdParam);
+        frontend()->scriptFailedToParse(scriptId, scriptURL, script.startLine, script.startColumn, script.endLine, script.endColumn, isContentScript, isInternalScript, sourceMapURLParam, hasSourceURLParam, languageParam, libraryIdParam);
 
     m_scripts.set(scriptId, script);
 
@@ -901,7 +900,7 @@ void DartInspectorDebuggerAgent::didParseSource(const String& scriptId, const Sc
         breakpointObject->getString(DartDebuggerAgentState::condition, &breakpoint.condition);
         RefPtr<TypeBuilder::Debugger::Location> location = resolveBreakpoint(it->key, scriptId, breakpoint, UserBreakpointSource);
         if (location)
-            m_frontend->breakpointResolved(it->key, location);
+            frontend()->breakpointResolved(it->key, location);
     }
 }
 
@@ -953,7 +952,7 @@ DartScriptDebugListener::SkipPauseRequest DartInspectorDebuggerAgent::didPause(D
         }
     }
 
-    m_frontend->paused(currentCallFrames(), m_breakReason, m_breakAuxData, hitBreakpointIds, nullptr);
+    frontend()->paused(currentCallFrames(), m_breakReason, m_breakAuxData, hitBreakpointIds, nullptr);
     m_javaScriptPauseScheduled = false;
     m_debuggerStepScheduled = false;
     m_steppingFromFramework = false;
@@ -975,7 +974,7 @@ void DartInspectorDebuggerAgent::didContinue()
     m_currentCallStack = 0;
     clearBreakDetails();
     // Already called by InspectorDebuggerAgent?
-    m_frontend->resumed();
+    frontend()->resumed();
 }
 
 bool DartInspectorDebuggerAgent::canBreakProgram()