Reland "Set multitexturing image threshold for PowerVR."

This is a reland of 06c8da41eb
Original change's description:
> Set multitexturing image threshold for PowerVR.
> 
> Change-Id: I2fd928f79e005c73151a9b915879ac561c3fadaf
> Reviewed-on: https://skia-review.googlesource.com/78400
> Commit-Queue: Brian Salomon <bsalomon@google.com>
> Reviewed-by: Robert Phillips <robertphillips@google.com>

Change-Id: Ib755e57833bf22e7feb612eb434eae3cac2e3f45
Reviewed-on: https://skia-review.googlesource.com/79263
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

src/gpu/gl/GrGLCaps.cpp

@@ -365,6 +365,14 @@ void GrGLCaps::init(const GrContextOptions& contextOptions,
             // but it doesn't clearly align with Pascal vs Maxwell vs Kepler.
             fShaderCaps->fDisableImageMultitexturingDstRectAreaThreshold = 150 * 150;
             break;
+        case kImagination_GrGLVendor:
+            // Two PowerVR Rogues, Nexus Player and Chromebook Cb5-312T (PowerVR GX6250), show that
+            // it is always a win to use multitexturing.
+            if (kPowerVRRogue_GrGLRenderer == ctxInfo.renderer()) {
+                fShaderCaps->fDisableImageMultitexturingDstRectAreaThreshold =
+                        std::numeric_limits<size_t>::max();
+            }
+            break;
         default:
             break;
     }