Expand all paths to be based off pdfium/ directory

This CL runs a script over the source and updates the include files to be
a full path from the pdfium/ directory.

BUG=pdfium:65
R=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1707923002 .
diff --git a/testing/embedder_test_timer_handling_delegate.h b/testing/embedder_test_timer_handling_delegate.h
index a704bd4..cb0c31b 100644
--- a/testing/embedder_test_timer_handling_delegate.h
+++ b/testing/embedder_test_timer_handling_delegate.h
@@ -10,8 +10,8 @@
 #include <utility>
 #include <vector>
 
-#include "embedder_test.h"
-#include "test_support.h"
+#include "testing/embedder_test.h"
+#include "testing/test_support.h"
 
 class EmbedderTestTimerHandlingDelegate : public EmbedderTest::Delegate {
  public: