diff --git a/gpu/command_buffer/service/framebuffer_manager.cc b/gpu/command_buffer/service/framebuffer_manager.cc
index 9d0d0e3780442..a9f881925a627 100644
--- a/gpu/command_buffer/service/framebuffer_manager.cc
+++ b/gpu/command_buffer/service/framebuffer_manager.cc
@@ -456,6 +456,33 @@ bool Framebuffer::HasUnclearedIntRenderbufferAttachments() const {
 
 void Framebuffer::ClearUnclearedIntRenderbufferAttachments(
     RenderbufferManager* renderbuffer_manager) {
+  // glClearBuffer*iv(GL_COLOR, i, ...) targets DRAW_BUFFERi, not
+  // COLOR_ATTACHMENTi (ES3 4.2.3): when DRAW_BUFFERi == GL_NONE the clear is a
+  // silent no-op. Point each draw buffer at its attachment before clearing so
+  // the clear actually lands, then restore the page-visible state.
+  base::HeapArray<GLenum> buffers =
+      base::HeapArray<GLenum>::Uninit(manager_->max_draw_buffers_);
+  for (uint32_t i = 0; i < manager_->max_draw_buffers_; ++i) {
+    buffers[i] = GL_NONE;
+  }
+  bool need_clear = false;
+  for (auto const& it : attachments_) {
+    if (!it.second->IsRenderbufferAttachment() || it.second->cleared() ||
+        !GLES2Util::IsIntegerFormat(it.second->internal_format())) {
+      continue;
+    }
+    if (it.first < GL_COLOR_ATTACHMENT0 ||
+        it.first >= GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_) {
+      continue;
+    }
+    buffers[it.first - GL_COLOR_ATTACHMENT0] = it.first;
+    need_clear = true;
+  }
+  if (!need_clear) {
+    return;
+  }
+  glDrawBuffersARB(manager_->max_draw_buffers_, buffers.data());
+
   for (AttachmentMap::const_iterator it = attachments_.begin();
        it != attachments_.end(); ++it) {
     if (!it->second->IsRenderbufferAttachment() || it->second->cleared())
@@ -464,8 +491,11 @@ void Framebuffer::ClearUnclearedIntRenderbufferAttachments(
     if (GLES2Util::IsIntegerFormat(internal_format)) {
       GLenum attaching_point = it->first;
       DCHECK_LE(static_cast<GLenum>(GL_COLOR_ATTACHMENT0), attaching_point);
-      DCHECK_GT(GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_,
-                attaching_point);
+      if (attaching_point >=
+          GL_COLOR_ATTACHMENT0 + manager_->max_draw_buffers_) {
+        // Can't be addressed via glClearBuffer*iv; leave it marked uncleared.
+        continue;
+      }
       GLint drawbuffer = it->first - GL_COLOR_ATTACHMENT0;
       if (GLES2Util::IsUnsignedIntegerFormat(internal_format)) {
         const GLuint kZero[] = { 0u, 0u, 0u, 0u };
@@ -478,6 +508,8 @@ void Framebuffer::ClearUnclearedIntRenderbufferAttachments(
       it->second->SetCleared(renderbuffer_manager, nullptr, true);
     }
   }
+
+  RestoreDrawBuffers();
 }
 
 bool Framebuffer::HasSRGBAttachments() const {