Add ContextProvider::InvalidateGrContext to reset GL state in GrContext

cc/output/context_provider.cc

Index: cc/output/context_provider.cc
diff --git a/cc/output/context_provider.cc b/cc/output/context_provider.cc
index 23a8e2c8fd33c50062f873ccef75a7ed2e8e7ab0..2cf9da208981170242edf4b1fbcd894701e8e85a 100644
--- a/cc/output/context_provider.cc
+++ b/cc/output/context_provider.cc
@@ -11,4 +11,8 @@ namespace cc {
 ContextProvider::Capabilities::Capabilities()
     : max_transfer_buffer_usage_bytes(std::numeric_limits<size_t>::max()) {}
 
+void ContextProvider::InvalidateGrContext(uint32_t state) {
+  DoInvalidateGrContext(state);

[piman, 2015/05/06 22:03:40]

Why this?
Instead you can have each derived class implement InvalidateGrContext

[CodeByThePound, 2015/05/06 22:27:55]

This is a pattern that allows the default argument to InvalidateGrContext and
not have to propagate it through the derived classes.  If default arguments are
not allowed then this mechanism can be removed.

+}
+
 }  // namespace cc