gpu: Workaround Adreno 420 bug with deleting current FBO.

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 121eb4b1c175fde5140901b3c7873d1c4bf58072..90e60f34145db325ccc47b11da697b2b6137ff9b 100644
--- a/gpu/command_buffer/service/gles2_cmd_decoder.cc
+++ b/gpu/command_buffer/service/gles2_cmd_decoder.cc
@@ -3099,11 +3099,16 @@ void GLES2DecoderImpl::DeleteFramebuffersHelper(
         GetFramebuffer(client_ids[ii]);
     if (framebuffer && !framebuffer->IsDeleted()) {
       if (framebuffer == framebuffer_state_.bound_draw_framebuffer.get()) {
-        framebuffer_state_.bound_draw_framebuffer = NULL;
-        framebuffer_state_.clear_state_dirty = true;
         GLenum target = supports_separate_framebuffer_binds ?
             GL_DRAW_FRAMEBUFFER_EXT : GL_FRAMEBUFFER;
+
+        // Unbind attachments on FBO before deletion.
+        if (workarounds().unbind_attachments_on_bound_render_fbo_delete)
+          framebuffer->UnbindAttachments(target);
+
         glBindFramebufferEXT(target, GetBackbufferServiceId());
+        framebuffer_state_.bound_draw_framebuffer = NULL;
+        framebuffer_state_.clear_state_dirty = true;
       }
       if (framebuffer == framebuffer_state_.bound_read_framebuffer.get()) {
         framebuffer_state_.bound_read_framebuffer = NULL;