Only report root frames in GetProcessToURLMap.

This allows the memory-infra UKMs to correctly report the URL of the root frame
for each process, since there is no way to report multiple URLs [for child
frames].

Bug: 730783
Change-Id: I342b3a76d543c8f9e4b0e2edc34f88d331e8b4e1
Reviewed-on: https://chromium-review.googlesource.com/601164
Commit-Queue: Erik Chen <erikchen@chromium.org>
Reviewed-by: Oystein Eftevaag <oysteine@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491904}

services/resource_coordinator/coordination_unit/coordination_unit_introspector_impl.cc

@@ -8,6 +8,7 @@
 
 #include "base/process/process_handle.h"
 #include "services/resource_coordinator/coordination_unit/coordination_unit_impl.h"
+#include "services/resource_coordinator/coordination_unit/frame_coordination_unit_impl.h"
 
 namespace resource_coordinator {
 
@@ -33,6 +34,10 @@ void CoordinationUnitIntrospectorImpl::GetProcessToURLMap(
         process_cu->GetAssociatedCoordinationUnitsOfType(
             CoordinationUnitType::kFrame);
     for (CoordinationUnitImpl* frame_cu : frame_cus) {
+      if (!CoordinationUnitImpl::ToFrameCoordinationUnit(frame_cu)
+               ->IsMainFrame()) {
+        continue;
+      }
       base::Value url_value = frame_cu->GetProperty(
           resource_coordinator::mojom::PropertyType::kURL);
       if (url_value.is_string()) {