Use angle::Result in front-end (Part 5)

Refactors gl::Buffer and implementation.

Bug: angleproject:2491
Change-Id: Ic6860dac2faf33067965e7117ea8e98dc6a8dc7a
Reviewed-on: https://chromium-review.googlesource.com/c/1283310
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/tests/perf_tests/IndexDataManagerTest.cpp b/src/tests/perf_tests/IndexDataManagerTest.cpp
index 93bee31..55d14b0 100644
--- a/src/tests/perf_tests/IndexDataManagerTest.cpp
+++ b/src/tests/perf_tests/IndexDataManagerTest.cpp
@@ -81,27 +81,28 @@
     MockBufferD3D(rx::BufferFactoryD3D *factory) : BufferD3D(mockState, factory), mData() {}
 
     // BufferImpl
-    gl::Error setData(const gl::Context *context,
-                      gl::BufferBinding target,
-                      const void *data,
-                      size_t size,
-                      gl::BufferUsage) override
+    angle::Result setData(const gl::Context *context,
+                          gl::BufferBinding target,
+                          const void *data,
+                          size_t size,
+                          gl::BufferUsage) override
     {
         mData.resize(size);
         if (data && size > 0)
         {
             memcpy(&mData[0], data, size);
         }
-        return gl::NoError();
+        return angle::Result::Continue();
     }
 
-    MOCK_METHOD5(setSubData,
-                 gl::Error(const gl::Context *, gl::BufferBinding, const void *, size_t, size_t));
+    MOCK_METHOD5(
+        setSubData,
+        angle::Result(const gl::Context *, gl::BufferBinding, const void *, size_t, size_t));
     MOCK_METHOD5(copySubData,
-                 gl::Error(const gl::Context *, BufferImpl *, GLintptr, GLintptr, GLsizeiptr));
-    MOCK_METHOD3(map, gl::Error(const gl::Context *context, GLenum, void **));
-    MOCK_METHOD5(mapRange, gl::Error(const gl::Context *, size_t, size_t, GLbitfield, void **));
-    MOCK_METHOD2(unmap, gl::Error(const gl::Context *context, GLboolean *));
+                 angle::Result(const gl::Context *, BufferImpl *, GLintptr, GLintptr, GLsizeiptr));
+    MOCK_METHOD3(map, angle::Result(const gl::Context *context, GLenum, void **));
+    MOCK_METHOD5(mapRange, angle::Result(const gl::Context *, size_t, size_t, GLbitfield, void **));
+    MOCK_METHOD2(unmap, angle::Result(const gl::Context *context, GLboolean *));
 
     // BufferD3D
     MOCK_METHOD1(markTransformFeedbackUsage, angle::Result(const gl::Context *));