When ignoring color input don't use vertex attribs on gpu

Also rename SolidWhite_ColorInput enum to be AllOnes_ColorInput to better reflect what it's use is

BUG=skia:
R=bsalomon@google.com

Author: egdaniel@google.com

Review URL: https://codereview.chromium.org/525433002
diff --git a/src/gpu/gl/GrGLProgramDesc.h b/src/gpu/gl/GrGLProgramDesc.h
index 4796d5a..aefcb50 100644
--- a/src/gpu/gl/GrGLProgramDesc.h
+++ b/src/gpu/gl/GrGLProgramDesc.h
@@ -99,7 +99,7 @@
 private:
     // Specifies where the initial color comes from before the stages are applied.
     enum ColorInput {
-        kSolidWhite_ColorInput,
+        kAllOnes_ColorInput,
         kAttribute_ColorInput,
         kUniform_ColorInput,