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/src/gpu/effects/GrEllipseEffect.fp b/src/gpu/effects/GrEllipseEffect.fp
index 256d0f4..8e8c766 100644
--- a/src/gpu/effects/GrEllipseEffect.fp
+++ b/src/gpu/effects/GrEllipseEffect.fp
@@ -6,7 +6,7 @@
  */
 
 @header {
-    #include "GrShaderCaps.h"
+    #include "src/gpu/GrShaderCaps.h"
 }
 
 layout(key) in GrClipEdgeType edgeType;