Continue using the RGB emulation path for IOSurfaces with Swiftshader.

Swiftshader with the validating command decoder do not fully emulate RGB on
BGRA IOSurfaces so use the old emulation paths in the validating command
decoder for this case.

BUG=995142

Change-Id: I6cb5053b0bd03d54866a50ec3a392be4b39057c3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1763238
Commit-Queue: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689553}

ui/gl/gl_image_io_surface.mm

@@ -170,7 +170,9 @@ GLImageIOSurface* GLImageIOSurface::Create(const gfx::Size& size,
     case kGLImplementationEGLGLES2:
     case kGLImplementationEGLANGLE:
     case kGLImplementationSwiftShaderGL:
-      return new GLImageIOSurfaceEGL(size, internalformat);
+      return new GLImageIOSurfaceEGL(
+          size, internalformat,
+          GetGLImplementation() == kGLImplementationSwiftShaderGL);
     default:
       break;
   }

ui/gl/gl_image_io_surface_egl.h

@@ -15,7 +15,9 @@ namespace gl {
 // EGL_ANGLE_iosurface_client_buffer extension to bind the IOSurface to textures
 class GL_EXPORT GLImageIOSurfaceEGL : public GLImageIOSurface {
  public:
-  GLImageIOSurfaceEGL(const gfx::Size& size, unsigned internalformat);
+  GLImageIOSurfaceEGL(const gfx::Size& size,
+                      unsigned internalformat,
+                      bool emulate_rgb);
 
   void ReleaseTexImage(unsigned target) override;
 
@@ -25,6 +27,12 @@ class GL_EXPORT GLImageIOSurfaceEGL : public GLImageIOSurface {
   bool CopyTexImage(unsigned target) override;
 
  private:
+  // If Swiftshader is being used, use the RGB emulation paths in the validating
+  // command decoder instead of creating the IOSurface with an RGB format. ANGLE
+  // handles the emulation internally.  This can be removed once Swiftshader is
+  // used as an ANGLE backend.
+  bool emulate_rgb_;
+
   EGLDisplay display_;
   EGLSurface pbuffer_;
   EGLConfig dummy_config_;

ui/gl/gl_image_io_surface_egl.mm

@@ -31,7 +31,8 @@ struct InternalFormatType {
 
 // Convert a gfx::BufferFormat to a (internal format, type) combination from the
 // EGL_ANGLE_iosurface_client_buffer extension spec.
-InternalFormatType BufferFormatToInternalFormatType(gfx::BufferFormat format) {
+InternalFormatType BufferFormatToInternalFormatType(gfx::BufferFormat format,
+                                                    bool emulate_rgb) {
   switch (format) {
     case gfx::BufferFormat::R_8:
       return {GL_RED, GL_UNSIGNED_BYTE};
@@ -40,7 +41,11 @@ InternalFormatType BufferFormatToInternalFormatType(gfx::BufferFormat format) {
     case gfx::BufferFormat::RG_88:
       return {GL_RG, GL_UNSIGNED_BYTE};
     case gfx::BufferFormat::BGRX_8888:
-      return {GL_RGB, GL_UNSIGNED_BYTE};
+      if (emulate_rgb) {
+        return {GL_BGRA_EXT, GL_UNSIGNED_BYTE};
+      } else {
+        return {GL_RGB, GL_UNSIGNED_BYTE};
+      }
     case gfx::BufferFormat::BGRA_8888:
     case gfx::BufferFormat::RGBA_8888:
       return {GL_BGRA_EXT, GL_UNSIGNED_BYTE};
@@ -67,8 +72,10 @@ InternalFormatType BufferFormatToInternalFormatType(gfx::BufferFormat format) {
 }  // anonymous namespace
 
 GLImageIOSurfaceEGL::GLImageIOSurfaceEGL(const gfx::Size& size,
-                                         unsigned internalformat)
+                                         unsigned internalformat,
+                                         bool emulate_rgb)
     : GLImageIOSurface(size, internalformat),
+      emulate_rgb_(emulate_rgb),
       display_(GLSurfaceEGL::GetHardwareDisplay()),
       pbuffer_(EGL_NO_SURFACE),
       dummy_config_(nullptr),
@@ -116,7 +123,8 @@ bool GLImageIOSurfaceEGL::BindTexImageImpl(unsigned internalformat) {
   // in the constructor if we're going to be used to bind plane 0 to a texture,
   // or to transform YUV to RGB.
   if (pbuffer_ == EGL_NO_SURFACE) {
-    InternalFormatType formatType = BufferFormatToInternalFormatType(format_);
+    InternalFormatType formatType =
+        BufferFormatToInternalFormatType(format_, emulate_rgb_);
 
     // clang-format off
     const EGLint attribs[] = {