Move GLSL-specific routines/classes to separate glsl directory

src/gpu/glsl/GrGLSL.cpp

+/*
+ * Copyright 2011 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrGLSL.h"
+#include "SkString.h"
+
+bool GrGLSLSupportsNamedFragmentShaderOutputs(GrGLSLGeneration gen) {
+    switch (gen) {
+        case k110_GrGLSLGeneration:
+            return false;
+        case k130_GrGLSLGeneration:
+        case k140_GrGLSLGeneration:
+        case k150_GrGLSLGeneration:
+        case k330_GrGLSLGeneration:
+        case k310es_GrGLSLGeneration:
+            return true;
+    }
+    return false;
+}
+
+void GrGLSLMulVarBy4f(SkString* outAppend, const char* vec4VarName, const GrGLSLExpr4& mulFactor) {
+    if (mulFactor.isOnes()) {
+        *outAppend = SkString();
+    }
+
+    if (mulFactor.isZeros()) {
+        outAppend->appendf("%s = vec4(0);", vec4VarName);
+    } else {
+        outAppend->appendf("%s *= %s;", vec4VarName, mulFactor.c_str());
+    }
+}