Attempt to disable clear-as-draw-workaround on iOS PowerVR.

This workaround was modified here: https://chromium.googlesource.com/skia.git/+/43f8bf0f784f4182ed0fca9053ecf570caf7ad70

We have a report that this triggered a rendering regression on iOS. I believe this workaround was enabled on PowerVR due to issues on Android and not iOS.


Change-Id: Iba4b589d8119f9e6106dec3504af156f536cb38c
Reviewed-on: https://skia-review.googlesource.com/66541
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
diff --git a/src/gpu/gl/GrGLCaps.cpp b/src/gpu/gl/GrGLCaps.cpp
index fd35827..4ba504c 100644
--- a/src/gpu/gl/GrGLCaps.cpp
+++ b/src/gpu/gl/GrGLCaps.cpp
@@ -562,12 +562,14 @@
         GR_GL_GetIntegerv(gli, GR_GL_MAX_WINDOW_RECTANGLES, &fMaxWindowRectangles);
     }
 
+#ifndef SK_BUILD_FOR_IOS
     if (kPowerVR54x_GrGLRenderer == ctxInfo.renderer() ||
         kPowerVRRogue_GrGLRenderer == ctxInfo.renderer() ||
         (kAdreno3xx_GrGLRenderer == ctxInfo.renderer() &&
          ctxInfo.driver() != kChromium_GrGLDriver)) {
         fUseDrawToClearColor = true;
     }
+#endif
 
     // A lot of GPUs have trouble with full screen clears (skbug.com/7195)
     if (kAMDRadeonHD7xxx_GrGLRenderer == ctxInfo.renderer() ||