Check for GL_EXT_geometry_shader on ES

BUG=skia:

Change-Id: If4f13af35679c048253c6c513a74e79be808dd74
Reviewed-on: https://skia-review.googlesource.com/8466
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index 7289d3d..aea875f 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -282,6 +282,8 @@
         shaderCaps->fShaderDerivativeSupport = ctxInfo.version() >= GR_GL_VER(3, 0) ||
             ctxInfo.hasExtension("GL_OES_standard_derivatives");
 
+        shaderCaps->fGeometryShaderSupport = ctxInfo.hasExtension("GL_EXT_geometry_shader");
+
         shaderCaps->fIntegerSupport = ctxInfo.version() >= GR_GL_VER(3, 0) &&
             ctxInfo.glslGeneration() >= k330_GrGLSLGeneration; // We use this value for GLSL ES 3.0.
     }