[WebLayer] Remove unused headers.

Change-Id: Id4288fe389c42ecd3c53d1cdc636cde4129e59ef
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2000921
Commit-Queue: Mugdha Lakhani <nator@chromium.org>
Reviewed-by: Tobias Sargeant <tobiasjs@chromium.org>
Cr-Commit-Position: refs/heads/master@{#732969}

weblayer/browser/browser_main_parts_impl.cc

@@ -15,7 +15,6 @@
 #include "content/public/browser/browser_thread.h"
 #include "content/public/browser/devtools_agent_host.h"
 #include "content/public/browser/render_process_host.h"
-#include "content/public/browser/storage_partition.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #include "content/public/common/url_constants.h"

weblayer/browser/content_browser_client_impl.cc

@@ -22,7 +22,6 @@
 #include "content/public/browser/generated_code_cache_settings.h"
 #include "content/public/browser/navigation_throttle.h"
 #include "content/public/browser/network_service_instance.h"
-#include "content/public/browser/storage_partition.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/service_names.mojom.h"
 #include "content/public/common/user_agent.h"