Add support for ES3 MSAA.

src/gpu/gl/GrGLCaps.cpp

Index: src/gpu/gl/GrGLCaps.cpp
===================================================================
--- src/gpu/gl/GrGLCaps.cpp	(revision 10891)
+++ src/gpu/gl/GrGLCaps.cpp	(working copy)
@@ -377,17 +377,21 @@
 
     fMSFBOType = kNone_MSFBOType;
     if (kDesktop_GrGLBinding != ctxInfo.binding()) {
-       if (ctxInfo.hasExtension("GL_CHROMIUM_framebuffer_multisample")) {
-           // chrome's extension is equivalent to the EXT msaa
-           // and fbo_blit extensions.
-           fMSFBOType = kDesktop_EXT_MSFBOType;
-       } else if (ctxInfo.hasExtension("GL_APPLE_framebuffer_multisample")) {
-           fMSFBOType = kES_Apple_MSFBOType;
-       } else if (ctxInfo.hasExtension("GL_EXT_multisampled_render_to_texture")) {
-           fMSFBOType = kES_EXT_MsToTexture_MSFBOType;
-       } else if (ctxInfo.hasExtension("GL_IMG_multisampled_render_to_texture")) {
-           fMSFBOType = kES_IMG_MsToTexture_MSFBOType;
-       }
+        // We prefer the EXT/IMG extension over ES3 MSAA because we've observed
+        // ES3 driver bugs on at least one device with a tiled GPU (N10).
+        if (ctxInfo.hasExtension("GL_EXT_multisampled_render_to_texture")) {
+            fMSFBOType = kES_EXT_MsToTexture_MSFBOType;
+        } else if (ctxInfo.hasExtension("GL_IMG_multisampled_render_to_texture")) {
+            fMSFBOType = kES_IMG_MsToTexture_MSFBOType;
+        } else if (!GR_GL_IGNORE_ES3_MSAA && ctxInfo.version() >= GR_GL_VER(3,0)) {
+            fMSFBOType = GrGLCaps::kES_3_0_MSFBOType;
+        } else if (ctxInfo.hasExtension("GL_CHROMIUM_framebuffer_multisample")) {
+            // chrome's extension is equivalent to the EXT msaa
+            // and fbo_blit extensions.
+            fMSFBOType = kDesktop_EXT_MSFBOType;
+        } else if (ctxInfo.hasExtension("GL_APPLE_framebuffer_multisample")) {
+            fMSFBOType = kES_Apple_MSFBOType;
+        }
     } else {
         if ((ctxInfo.version() >= GR_GL_VER(3,0)) ||
             ctxInfo.hasExtension("GL_ARB_framebuffer_object")) {
@@ -560,6 +564,7 @@
         "None",
         "ARB",
         "EXT",
+        "ES 3.0",
         "Apple",
         "IMG MS To Texture",
         "EXT MS To Texture",
@@ -567,9 +572,10 @@
     GR_STATIC_ASSERT(0 == kNone_MSFBOType);
     GR_STATIC_ASSERT(1 == kDesktop_ARB_MSFBOType);
     GR_STATIC_ASSERT(2 == kDesktop_EXT_MSFBOType);
-    GR_STATIC_ASSERT(3 == kES_Apple_MSFBOType);
-    GR_STATIC_ASSERT(4 == kES_IMG_MsToTexture_MSFBOType);
-    GR_STATIC_ASSERT(5 == kES_EXT_MsToTexture_MSFBOType);
+    GR_STATIC_ASSERT(3 == kES_3_0_MSFBOType);
+    GR_STATIC_ASSERT(4 == kES_Apple_MSFBOType);
+    GR_STATIC_ASSERT(5 == kES_IMG_MsToTexture_MSFBOType);
+    GR_STATIC_ASSERT(6 == kES_EXT_MsToTexture_MSFBOType);
     GR_STATIC_ASSERT(GR_ARRAY_COUNT(kMSFBOExtStr) == kLast_MSFBOType + 1);
 
     static const char* kFBFetchTypeStr[] = {