Adding unit test for verifying copy on write in SkSurface + bug fix in SkCanvas::clear

tests/TestClassDef.h

 
 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 /*  This file is meant to be included by .cpp files, so it can spew out a
     customized class + global definition.
 
     e.g.
     #include "TestClassDef.h"
     DEFINE_TESTCLASS("MyTest", MyTestClass, MyTestFunction)
 
     where MyTestFunction is declared as
 
         void MyTestFunction(skiatest::Reporter*)
 */
 
 #define DEFINE_TESTCLASS(uiname, classname, function)                                   \
     namespace skiatest {                                                                \
         class classname : public Test {                                                 \
         public:                                                                         \
             static Test* Factory(void*) { return SkNEW(classname); }                    \
         protected:                                                                      \
             virtual void onGetName(SkString* name) SK_OVERRIDE { name->set(uiname); }   \
             virtual void onRun(Reporter* reporter) SK_OVERRIDE { function(reporter); }  \
         };                                                                              \
-        static TestRegistry gReg(classname::Factory);                                   \
+        static TestRegistry gReg_##classname(classname::Factory);                       \
     }
 
 #define DEFINE_GPUTESTCLASS(uiname, classname, function)                                \
     namespace skiatest {                                                                \
         class classname : public GpuTest {                                              \
         public:                                                                         \
             static Test* Factory(void*) { return SkNEW(classname); }                    \
         protected:                                                                      \
             virtual void onGetName(SkString* name) SK_OVERRIDE { name->set(uiname); }   \
             virtual void onRun(Reporter* reporter) SK_OVERRIDE {                        \
                 function(reporter, GetGrContextFactory());                              \
             }                                                                           \
         };                                                                              \
-        static TestRegistry gReg(classname::Factory);                                   \
+        static TestRegistry gReg_##classname(classname::Factory);                       \
     }