Revert "Switched highp float to highfloat and mediump float to half."

This reverts commit 88d99c63878c2d3d340120f0321676f72afcb4f0.

Reason for revert: Believed to be causing unit test failures in Chrome roll:

https://build.chromium.org/p/tryserver.chromium.android/builders/linux_android_rel_ng/builds/364433
https://luci-logdog.appspot.com/v/?s=chromium%2Fbb%2Ftryserver.chromium.android%2Flinux_android_rel_ng%2F364433%2F%2B%2Frecipes%2Fsteps%2Fcontent_browsertests__with_patch__on_Android%2F0%2Flogs%2FWebRtcCaptureFromElementBrowserTest.VerifyCanvasWebGLCaptureColor%2F0

Original change's description:
> Switched highp float to highfloat and mediump float to half.
> 
> The ultimate goal is to end up with "float" and "half", but this
> intermediate step uses "highfloat" so that it is clear if I missed a
> "float" somewhere. Once this lands, a subsequent CL will switch all
> "highfloats" back to "floats".
> 
> Bug: skia:
> Change-Id: Ia13225c7a0a0a2901e07665891c473d2500ddcca
> Reviewed-on: https://skia-review.googlesource.com/31000
> Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
> Reviewed-by: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,csmartdalton@google.com,ethannicholas@google.com

Change-Id: I8bfa97547ac3920d433665f161d27df3f15c83aa
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: skia:
Reviewed-on: https://skia-review.googlesource.com/35705
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
diff --git a/tests/ImageStorageTest.cpp b/tests/ImageStorageTest.cpp
index 8a6023f..6d5cab0 100644
--- a/tests/ImageStorageTest.cpp
+++ b/tests/ImageStorageTest.cpp
@@ -58,13 +58,13 @@
                     const TestFP& tfp = args.fFp.cast<TestFP>();
                     GrGLSLFPFragmentBuilder* fb = args.fFragBuilder;
                     SkString imageLoadStr;
-                    fb->codeAppend("highfloat2 coord = sk_FragCoord.xy;");
+                    fb->codeAppend("highp float2 coord = sk_FragCoord.xy;");
                     fb->appendImageStorageLoad(&imageLoadStr, args.fImageStorages[0],
                                                "int2(coord)");
                     if (GrPixelConfigIsSint(tfp.fImageStorageAccess.peekTexture()->config())) {
                         // Map the signed bytes so that when then get read back as unorm values they
                         // will have their original bit pattern.
-                        fb->codeAppendf("int4 ivals = %s;", imageLoadStr.c_str());
+                        fb->codeAppendf("highp int4 ivals = %s;", imageLoadStr.c_str());
                         // NV gives a linker error for this:
                         // fb->codeAppend("ivals +=
                         //                "mix(int4(0), int4(256), lessThan(ivals, int4(0)));");
@@ -72,7 +72,7 @@
                         fb->codeAppend("if (ivals.g < 0) { ivals.g += 256; }");
                         fb->codeAppend("if (ivals.b < 0) { ivals.b += 256; }");
                         fb->codeAppend("if (ivals.a < 0) { ivals.a += 256; }");
-                        fb->codeAppendf("%s = half4(ivals)/255;", args.fOutputColor);
+                        fb->codeAppendf("%s = float4(ivals)/255;", args.fOutputColor);
                     } else {
                         fb->codeAppendf("%s = %s;", args.fOutputColor, imageLoadStr.c_str());
                     }