Revert of [Command buffer]: Generate INVALID_OPERATION if designated attachments in read fb miss image

gpu/command_buffer/service/gles2_cmd_decoder.cc

Index: gpu/command_buffer/service/gles2_cmd_decoder.cc
diff --git a/gpu/command_buffer/service/gles2_cmd_decoder.cc b/gpu/command_buffer/service/gles2_cmd_decoder.cc
index 38f6b5f166661888395a01c26dcf1aa5f44f02e5..ba6b5efb598496ebad28ea7a4c14c37be6442a83 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -7910,10 +7910,6 @@
     return;
   }
 
-  // Detect that designated read/depth/stencil buffer in read framebuffer miss
-  // image, and the corresponding buffers in draw framebuffer have image.
-  bool read_framebuffer_miss_image = false;
-
   // Check whether read framebuffer and draw framebuffer have identical image
   // TODO(yunchao): consider doing something like CheckFramebufferStatus().
   // We cache the validation results, and if read_framebuffer doesn't change,
@@ -7937,18 +7933,6 @@
     is_feedback_loop = FeedbackLoopTrue;
   } else if (!read_framebuffer || !draw_framebuffer) {
     is_feedback_loop = FeedbackLoopFalse;
-    if (read_framebuffer) {
-      if (((mask & GL_COLOR_BUFFER_BIT) != 0 &&
-          !GetBoundReadFramebufferInternalFormat()) ||
-          ((mask & GL_DEPTH_BUFFER_BIT) != 0 &&
-          !read_framebuffer->GetAttachment(GL_DEPTH_ATTACHMENT) &&
-          BoundFramebufferHasDepthAttachment()) ||
-          ((mask & GL_STENCIL_BUFFER_BIT) != 0 &&
-          !read_framebuffer->GetAttachment(GL_STENCIL_ATTACHMENT) &&
-          BoundFramebufferHasStencilAttachment())) {
-        read_framebuffer_miss_image = true;
-      }
-    }
   } else {
     DCHECK(read_framebuffer && draw_framebuffer);
     if ((mask & GL_DEPTH_BUFFER_BIT) != 0) {
@@ -7958,9 +7942,6 @@
           draw_framebuffer->GetAttachment(GL_DEPTH_ATTACHMENT);
       if (!depth_buffer_draw || !depth_buffer_read) {
         mask &= ~GL_DEPTH_BUFFER_BIT;
-        if (depth_buffer_draw) {
-          read_framebuffer_miss_image = true;
-        }
       } else if (depth_buffer_draw->IsSameAttachment(depth_buffer_read)) {
         is_feedback_loop = FeedbackLoopTrue;
       }
@@ -7972,14 +7953,11 @@
           draw_framebuffer->GetAttachment(GL_STENCIL_ATTACHMENT);
       if (!stencil_buffer_draw || !stencil_buffer_read) {
         mask &= ~GL_STENCIL_BUFFER_BIT;
-        if (stencil_buffer_draw) {
-          read_framebuffer_miss_image = true;
-        }
       } else if (stencil_buffer_draw->IsSameAttachment(stencil_buffer_read)) {
         is_feedback_loop = FeedbackLoopTrue;
       }
     }
-    if (!mask && !read_framebuffer_miss_image)
+    if (!mask)
       return;
   }
 
@@ -8014,9 +7992,6 @@
       GLenum dst_type = GetBoundColorDrawBufferType(static_cast<GLint>(ii));
       if (dst_format == 0)
         continue;
-      if (!src_internal_format) {
-        read_framebuffer_miss_image = true;
-      }
       if (GetColorEncodingFromInternalFormat(dst_format) == GL_SRGB)
         draw_buffers_has_srgb = true;
       if (read_buffer_samples > 0 &&
@@ -8054,11 +8029,6 @@
   if (is_feedback_loop == FeedbackLoopTrue) {
     LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name,
         "source buffer and destination buffers are identical");
-    return;
-  }
-  if (read_framebuffer_miss_image == true) {
-    LOCAL_SET_GL_ERROR(GL_INVALID_OPERATION, func_name,
-       "The designated attachment point(s) in read framebuffer miss image");
     return;
   }