Add support for GL_EXT_raster_multisample

src/gpu/GrCaps.cpp

Index: src/gpu/GrCaps.cpp
diff --git a/src/gpu/GrCaps.cpp b/src/gpu/GrCaps.cpp
index f4c64c3333258f293af520665e8143377ae3cfda..46f49357c77d4d6fd09a25a63ff4a03ac606f99f 100644
--- a/src/gpu/GrCaps.cpp
+++ b/src/gpu/GrCaps.cpp
@@ -106,6 +106,7 @@ GrCaps::GrCaps(const GrContextOptions& options) {
     fMaxTextureSize = 1;
     fMaxColorSampleCount = 0;
     fMaxStencilSampleCount = 0;
+    fMaxRasterSamples = 0;
 
     fSuppressPrints = options.fSuppressPrints;
     fImmediateFlush = options.fImmediateMode;
@@ -178,6 +179,7 @@ SkString GrCaps::dump() const {
     r.appendf("Max Render Target Size             : %d\n", fMaxRenderTargetSize);
     r.appendf("Max Color Sample Count             : %d\n", fMaxColorSampleCount);
     r.appendf("Max Stencil Sample Count           : %d\n", fMaxStencilSampleCount);
+    r.appendf("Max Raster Samples                 : %d\n", fMaxRasterSamples);
 
     static const char* kBlendEquationSupportNames[] = {
         "Basic",