Use angle::Result in front-end (Part 3)

Handles the gl::Framebuffer class and its implementation.

Bug: angleproject:2491
Change-Id: I3b9c0609e9277264ccdb370596500562df3b7d15
Reviewed-on: https://chromium-review.googlesource.com/c/1280743
Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
diff --git a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
index ba09d2e..32caca6 100644
--- a/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
+++ b/src/libANGLE/renderer/d3d/FramebufferD3D.cpp
@@ -101,16 +101,16 @@
 {
 }
 
-gl::Error FramebufferD3D::clear(const gl::Context *context, GLbitfield mask)
+angle::Result FramebufferD3D::clear(const gl::Context *context, GLbitfield mask)
 {
     ClearParameters clearParams = GetClearParameters(context->getGLState(), mask);
     return clearImpl(context, clearParams);
 }
 
-gl::Error FramebufferD3D::clearBufferfv(const gl::Context *context,
-                                        GLenum buffer,
-                                        GLint drawbuffer,
-                                        const GLfloat *values)
+angle::Result FramebufferD3D::clearBufferfv(const gl::Context *context,
+                                            GLenum buffer,
+                                            GLint drawbuffer,
+                                            const GLfloat *values)
 {
     // glClearBufferfv can be called to clear the color buffer or depth buffer
     ClearParameters clearParams = GetClearParameters(context->getGLState(), 0);
@@ -134,10 +134,10 @@
     return clearImpl(context, clearParams);
 }
 
-gl::Error FramebufferD3D::clearBufferuiv(const gl::Context *context,
-                                         GLenum buffer,
-                                         GLint drawbuffer,
-                                         const GLuint *values)
+angle::Result FramebufferD3D::clearBufferuiv(const gl::Context *context,
+                                             GLenum buffer,
+                                             GLint drawbuffer,
+                                             const GLuint *values)
 {
     // glClearBufferuiv can only be called to clear a color buffer
     ClearParameters clearParams = GetClearParameters(context->getGLState(), 0);
@@ -151,10 +151,10 @@
     return clearImpl(context, clearParams);
 }
 
-gl::Error FramebufferD3D::clearBufferiv(const gl::Context *context,
-                                        GLenum buffer,
-                                        GLint drawbuffer,
-                                        const GLint *values)
+angle::Result FramebufferD3D::clearBufferiv(const gl::Context *context,
+                                            GLenum buffer,
+                                            GLint drawbuffer,
+                                            const GLint *values)
 {
     // glClearBufferiv can be called to clear the color buffer or stencil buffer
     ClearParameters clearParams = GetClearParameters(context->getGLState(), 0);
@@ -178,11 +178,11 @@
     return clearImpl(context, clearParams);
 }
 
-gl::Error FramebufferD3D::clearBufferfi(const gl::Context *context,
-                                        GLenum buffer,
-                                        GLint drawbuffer,
-                                        GLfloat depth,
-                                        GLint stencil)
+angle::Result FramebufferD3D::clearBufferfi(const gl::Context *context,
+                                            GLenum buffer,
+                                            GLint drawbuffer,
+                                            GLfloat depth,
+                                            GLint stencil)
 {
     // glClearBufferfi can only be called to clear a depth stencil buffer
     ClearParameters clearParams   = GetClearParameters(context->getGLState(), 0);
@@ -240,20 +240,20 @@
     return implementationFormatInfo.getReadPixelsType(context->getClientVersion());
 }
 
-gl::Error FramebufferD3D::readPixels(const gl::Context *context,
-                                     const gl::Rectangle &origArea,
-                                     GLenum format,
-                                     GLenum type,
-                                     void *pixels)
+angle::Result FramebufferD3D::readPixels(const gl::Context *context,
+                                         const gl::Rectangle &area,
+                                         GLenum format,
+                                         GLenum type,
+                                         void *pixels)
 {
     // Clip read area to framebuffer.
     const gl::Extents fbSize = getState().getReadAttachment()->getSize();
     const gl::Rectangle fbRect(0, 0, fbSize.width, fbSize.height);
-    gl::Rectangle area;
-    if (!ClipRectangle(origArea, fbRect, &area))
+    gl::Rectangle clippedArea;
+    if (!ClipRectangle(area, fbRect, &clippedArea))
     {
         // nothing to read
-        return gl::NoError();
+        return angle::Result::Continue();
     }
 
     const gl::PixelPackState &packState = context->getGLState().getPackState();
@@ -264,24 +264,24 @@
 
     GLuint outputPitch = 0;
     ANGLE_CHECK_HR_MATH(contextD3D,
-                        sizedFormatInfo.computeRowPitch(type, origArea.width, packState.alignment,
+                        sizedFormatInfo.computeRowPitch(type, area.width, packState.alignment,
                                                         packState.rowLength, &outputPitch));
 
     GLuint outputSkipBytes = 0;
     ANGLE_CHECK_HR_MATH(contextD3D, sizedFormatInfo.computeSkipBytes(
                                         type, outputPitch, 0, packState, false, &outputSkipBytes));
-    outputSkipBytes +=
-        (area.x - origArea.x) * sizedFormatInfo.pixelBytes + (area.y - origArea.y) * outputPitch;
+    outputSkipBytes += (clippedArea.x - area.x) * sizedFormatInfo.pixelBytes +
+                       (clippedArea.y - area.y) * outputPitch;
 
-    return readPixelsImpl(context, area, format, type, outputPitch, packState,
+    return readPixelsImpl(context, clippedArea, format, type, outputPitch, packState,
                           static_cast<uint8_t *>(pixels) + outputSkipBytes);
 }
 
-gl::Error FramebufferD3D::blit(const gl::Context *context,
-                               const gl::Rectangle &sourceArea,
-                               const gl::Rectangle &destArea,
-                               GLbitfield mask,
-                               GLenum filter)
+angle::Result FramebufferD3D::blit(const gl::Context *context,
+                                   const gl::Rectangle &sourceArea,
+                                   const gl::Rectangle &destArea,
+                                   GLbitfield mask,
+                                   GLenum filter)
 {
     const auto &glState                      = context->getGLState();
     const gl::Framebuffer *sourceFramebuffer = glState.getReadFramebuffer();
@@ -290,7 +290,7 @@
                        (mask & GL_DEPTH_BUFFER_BIT) != 0, (mask & GL_STENCIL_BUFFER_BIT) != 0,
                        filter, sourceFramebuffer));
 
-    return gl::NoError();
+    return angle::Result::Continue();
 }
 
 bool FramebufferD3D::checkStatus(const gl::Context *context) const