rewrite includes to not need so much -Ifoo

Current strategy: everything from the top

Things to look at first are the manual changes:

   - added tools/rewrite_includes.py
   - removed -Idirectives from BUILD.gn
   - various compile.sh simplifications
   - tweak tools/embed_resources.py
   - update gn/find_headers.py to write paths from the top
   - update gn/gn_to_bp.py SkUserConfig.h layout
     so that #include "include/config/SkUserConfig.h" always
     gets the header we want.

No-Presubmit: true
Change-Id: I73a4b181654e0e38d229bc456c0d0854bae3363e
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209706
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Hal Canary <halcanary@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
diff --git a/tests/ProxyTest.cpp b/tests/ProxyTest.cpp
index c65d221..bd646e8 100644
--- a/tests/ProxyTest.cpp
+++ b/tests/ProxyTest.cpp
@@ -7,20 +7,20 @@
 
 // This is a GPU-backend specific test.
 
-#include "Test.h"
+#include "tests/Test.h"
 
-#include "GrBackendSurface.h"
-#include "GrContextPriv.h"
-#include "GrProxyProvider.h"
-#include "GrRenderTargetPriv.h"
-#include "GrRenderTargetProxy.h"
-#include "GrResourceProvider.h"
-#include "GrSurfacePriv.h"
-#include "GrSurfaceProxyPriv.h"
-#include "GrTexture.h"
-#include "GrTextureProxy.h"
-#include "SkGr.h"
-#include "gl/GrGLDefines.h"
+#include "include/gpu/GrBackendSurface.h"
+#include "include/gpu/GrTexture.h"
+#include "include/private/GrRenderTargetProxy.h"
+#include "include/private/GrTextureProxy.h"
+#include "src/gpu/GrContextPriv.h"
+#include "src/gpu/GrProxyProvider.h"
+#include "src/gpu/GrRenderTargetPriv.h"
+#include "src/gpu/GrResourceProvider.h"
+#include "src/gpu/GrSurfacePriv.h"
+#include "src/gpu/GrSurfaceProxyPriv.h"
+#include "src/gpu/SkGr.h"
+#include "src/gpu/gl/GrGLDefines.h"
 
 // Check that the surface proxy's member vars are set as expected
 static void check_surface(skiatest::Reporter* reporter,