Use C++11 raw string literals instead of SHADER_SOURCE macro

This is better in many ways:
1. It doesn't confuse clang format
2. \n doesn't need to be included after preprocessor directives like
   the version directive.
3. It's using built-in functionality instead of something custom.

Raw string literals should be the preferred way to include shader
source in C++ files going forward.

BUG=angleproject:2157
TEST=angle_end2end_tests

Change-Id: I8b236a6e2d5c25d920297e5bc5b5b143eddeba1f
Reviewed-on: https://chromium-review.googlesource.com/671046
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Olli Etuaho <oetuaho@nvidia.com>
diff --git a/src/tests/gl_tests/SimpleOperationTest.cpp b/src/tests/gl_tests/SimpleOperationTest.cpp
index a22b8e1..d5850d8 100644
--- a/src/tests/gl_tests/SimpleOperationTest.cpp
+++ b/src/tests/gl_tests/SimpleOperationTest.cpp
@@ -54,14 +54,12 @@
 
 TEST_P(SimpleOperationTest, CompileVertexShader)
 {
-    const std::string source = SHADER_SOURCE
-    (
-        attribute vec4 a_input;
+    const std::string source =
+        R"(attribute vec4 a_input;
         void main()
         {
             gl_Position = a_input;
-        }
-    );
+        })";
 
     GLuint shader = CompileShader(GL_VERTEX_SHADER, source);
     EXPECT_NE(shader, 0u);
@@ -72,15 +70,13 @@
 
 TEST_P(SimpleOperationTest, CompileFragmentShader)
 {
-    const std::string source = SHADER_SOURCE
-    (
-        precision mediump float;
+    const std::string source =
+        R"(precision mediump float;
         varying vec4 v_input;
         void main()
         {
             gl_FragColor = v_input;
-        }
-    );
+        })";
 
     GLuint shader = CompileShader(GL_FRAGMENT_SHADER, source);
     EXPECT_NE(shader, 0u);
@@ -91,21 +87,17 @@
 
 TEST_P(SimpleOperationTest, LinkProgram)
 {
-    const std::string vsSource = SHADER_SOURCE
-    (
-        void main()
+    const std::string vsSource =
+        R"(void main()
         {
             gl_Position = vec4(1.0, 1.0, 1.0, 1.0);
-        }
-    );
+        })";
 
-    const std::string fsSource = SHADER_SOURCE
-    (
-        void main()
+    const std::string fsSource =
+        R"(void main()
         {
             gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
-        }
-    );
+        })";
 
     GLuint program = CompileProgram(vsSource, fsSource);
     EXPECT_NE(program, 0u);
@@ -123,23 +115,19 @@
         return;
     }
 
-    const std::string vsSource = SHADER_SOURCE
-    (
-        void main()
+    const std::string vsSource =
+        R"(void main()
         {
             gl_Position = vec4(1.0, 1.0, 1.0, 1.0);
-        }
-    );
+        })";
 
-    const std::string fsSource = SHADER_SOURCE
-    (
-        precision mediump float;
+    const std::string fsSource =
+        R"(precision mediump float;
         uniform vec4 u_input;
         void main()
         {
             gl_FragColor = u_input;
-        }
-    );
+        })";
 
     GLuint program = CompileProgram(vsSource, fsSource);
     EXPECT_NE(program, 0u);
@@ -161,22 +149,18 @@
         return;
     }
 
-    const std::string vsSource = SHADER_SOURCE
-    (
-        attribute vec4 a_input;
+    const std::string vsSource =
+        R"(attribute vec4 a_input;
         void main()
         {
             gl_Position = a_input;
-        }
-    );
+        })";
 
-    const std::string fsSource = SHADER_SOURCE
-    (
-        void main()
+    const std::string fsSource =
+        R"(void main()
         {
             gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
-        }
-    );
+        })";
 
     GLuint program = CompileProgram(vsSource, fsSource);
     EXPECT_NE(program, 0u);