Blink GC plugin: Don't check conditions on invalid compilation units.

BUG=421958, 334149
R=hans@chromium.org, haraken@chromium.org

Review URL: https://codereview.chromium.org/641353002

Cr-Commit-Position: refs/heads/master@{#299084}

tools/clang/blink_gc_plugin/BlinkGCPlugin.cpp

@@ -861,6 +861,10 @@ class BlinkGCPluginConsumer : public ASTConsumer {
   }
 
   void HandleTranslationUnit(ASTContext& context) override {
+    // Don't run the plugin if the compilation unit is already invalid.
+    if (diagnostic_.hasErrorOccurred())
+      return;
+
     CollectVisitor visitor;
     visitor.TraverseDecl(context.getTranslationUnitDecl());
 

tools/clang/blink_gc_plugin/tests/crash_on_invalid.cpp

+// Copyright 2014 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 "crash_on_invalid.h"
+
+// Nothing to define.

tools/clang/blink_gc_plugin/tests/crash_on_invalid.h

+// Copyright 2014 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.
+
+// Regression test for http://crbug.com/421958
+
+#ifndef CRASH_ON_INVALID_H_
+#define CRASH_ON_INVALID_H_
+
+namespace blink {
+
+class Visitor;
+class GamepadCommon {};
+class ScriptWrappable {};
+
+class Gamepad final : public GarbageCollectedFinalized<Gamepad>,
+                      public GamepadCommon,
+                      public ScriptWrappable {
+public:
+    virtual const WrapperTypeInfo *wrapperTypeInfo() const {}
+    void trace(Visitor *);
+};
+
+}
+
+#endif

tools/clang/blink_gc_plugin/tests/crash_on_invalid.txt

+