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>

1 files changed, 39 insertions, 1 deletions

diff --git a/src/sksl/SkSLParser.cpp b/src/sksl/SkSLParser.cpp
index dd044cde4e..f712b34e1a 100644
--- a/src/sksl/SkSLParser.cpp
+++ b/src/sksl/SkSLParser.cpp
@@ -49,6 +49,7 @@ static_assert(YY_FLEX_MAJOR_VERSION * 10000 + YY_FLEX_MINOR_VERSION * 100 +
 #include "ast/SkSLASTIntLiteral.h"
 #include "ast/SkSLASTModifiersDeclaration.h"
 #include "ast/SkSLASTParameter.h"
+#include "ast/SkSLASTPrecision.h"
 #include "ast/SkSLASTPrefixExpression.h"
 #include "ast/SkSLASTReturnStatement.h"
 #include "ast/SkSLASTSection.h"
@@ -108,13 +109,20 @@ Parser::~Parser() {
     layoutlex_destroy(fLayoutScanner);
 }
 
-/* (directive | section | declaration)* END_OF_FILE */
+/* (precision | directive | section | declaration)* END_OF_FILE */
 std::vector<std::unique_ptr<ASTDeclaration>> Parser::file() {
     std::vector<std::unique_ptr<ASTDeclaration>> result;
     for (;;) {
         switch (this->peek().fKind) {
             case Token::END_OF_FILE:
                 return result;
+            case Token::PRECISION: {
+                std::unique_ptr<ASTDeclaration> precision = this->precision();
+                if (precision) {
+                    result.push_back(std::move(precision));
+                }
+                break;
+            }
             case Token::DIRECTIVE: {
                 std::unique_ptr<ASTDeclaration> decl = this->directive();
                 if (decl) {
@@ -230,6 +238,36 @@ bool Parser::isType(const String& name) {
     return nullptr != fTypes[name];
 }
 
+/* PRECISION (LOWP | MEDIUMP | HIGHP) type SEMICOLON */
+std::unique_ptr<ASTDeclaration> Parser::precision() {
+    if (!this->expect(Token::PRECISION, "'precision'")) {
+        return nullptr;
+    }
+    Modifiers::Flag result;
+    Token p = this->nextToken();
+    switch (p.fKind) {
+        case Token::LOWP:
+            result = Modifiers::kLowp_Flag;
+            break;
+        case Token::MEDIUMP:
+            result = Modifiers::kMediump_Flag;
+            break;
+        case Token::HIGHP:
+            result = Modifiers::kHighp_Flag;
+            break;
+        default:
+            this->error(p.fPosition, "expected 'lowp', 'mediump', or 'highp', but found '" +
+                                     p.fText + "'");
+            return nullptr;
+    }
+    // FIXME handle the type
+    if (!this->type()) {
+        return nullptr;
+    }
+    this->expect(Token::SEMICOLON, "';'");
+    return std::unique_ptr<ASTDeclaration>(new ASTPrecision(p.fPosition, result));
+}
+
 /* DIRECTIVE(#version) INT_LITERAL ("es" | "compatibility")? |
    DIRECTIVE(#extension) IDENTIFIER COLON IDENTIFIER */
 std::unique_ptr<ASTDeclaration> Parser::directive() {