Move GraphicsContextTest to platform/ and fix the test environment.

Source/platform/testing/RunAllTests.cpp

Index: Source/platform/testing/RunAllTests.cpp
diff --git a/Source/wtf/testing/RunAllTests.cpp b/Source/platform/testing/RunAllTests.cpp
similarity index 92%
copy from Source/wtf/testing/RunAllTests.cpp
copy to Source/platform/testing/RunAllTests.cpp
index 5d27780e99d586068c6249d6eff297fda1cbd7d9..1b5d88106a327ec36de2c1524b6adcca133a4309 100644
--- a/Source/wtf/testing/RunAllTests.cpp
+++ b/Source/platform/testing/RunAllTests.cpp
@@ -30,6 +30,7 @@
 
 #include "config.h"
 
+#include "platform/TestingPlatformSupport.h"
 #include "wtf/CryptographicallyRandomNumber.h"
 #include "wtf/MainThread.h"
 #include "wtf/WTF.h"
@@ -51,5 +52,9 @@ int main(int argc, char** argv)
     WTF::setRandomSource(AlwaysZeroNumberSource);
     WTF::initialize(CurrentTime, 0);
     WTF::initializeMainThread(0);
+
+    WebCore::TestingPlatformSupport::Config platformConfig;
+    WebCore::TestingPlatformSupport platform(platformConfig);
+
     return base::RunUnitTestsUsingBaseTestSuite(argc, argv);
 }