[DevTools] Fix crash when runtime.evaluate is called with contextId = 0

third_party/WebKit/Source/platform/v8_inspector/V8InspectorSessionImpl.cpp

 // Copyright 2016 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 "platform/v8_inspector/V8InspectorSessionImpl.h"
 
 #include "platform/v8_inspector/InjectedScript.h"
 #include "platform/v8_inspector/InjectedScriptHost.h"
 #include "platform/v8_inspector/InspectedContext.h"
 #include "platform/v8_inspector/RemoteObjectId.h"
@@ skipping 71 matching lines @@
         keys.append(idContext.first);
     for (auto& key : keys) {
         contexts = m_debugger->contextGroup(m_contextGroupId);
         if (contexts && contexts->contains(key))
             contexts->get(key)->discardInjectedScript(); // This may destroy some contexts.
     }
 }
 
 InjectedScript* V8InspectorSessionImpl::findInjectedScript(ErrorString* errorString, int contextId)
 {
-    const V8DebuggerImpl::ContextByIdMap* contexts = m_debugger->contextGroup(m_contextGroupId);
-    if (!contexts || !contexts->contains(contextId)) {
-        *errorString = "Inspected frame has gone";
+    if (!contextId) {
+        *errorString = "Cannot find context with specified id";
         return nullptr;
     }
 
+    const V8DebuggerImpl::ContextByIdMap* contexts = m_debugger->contextGroup(m_contextGroupId);
+    if (!contexts || !contexts->contains(contextId)) {
+        *errorString = "Cannot find context with specified id";
+        return nullptr;
+    }
+
     InspectedContext* context = contexts->get(contextId);
     if (!context->getInjectedScript()) {
         context->createInjectedScript(m_injectedScriptHost.get());
         if (!context->getInjectedScript()) {
             *errorString = "Cannot access specified execution context";
             return nullptr;
         }
         if (m_customObjectFormatterEnabled)
             context->getInjectedScript()->setCustomObjectFormatterEnabled(true);
     }
@@ skipping 45 matching lines @@
 void V8InspectorSessionImpl::reportAllContexts(V8RuntimeAgentImpl* agent)
 {
     const V8DebuggerImpl::ContextByIdMap* contexts = m_debugger->contextGroup(m_contextGroupId);
     if (!contexts)
         return;
     for (auto& idContext : *contexts)
         agent->reportExecutionContextCreated(idContext.second);
 }
 
 } // namespace blink