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_mock_delegate.h b/testing/embedder_test_mock_delegate.h
index 47e795a..4d43b5c 100644
--- a/testing/embedder_test_mock_delegate.h
+++ b/testing/embedder_test_mock_delegate.h
@@ -5,7 +5,7 @@
 #ifndef TESTING_EMBEDDER_TEST_MOCK_DELEGATE_H_
 #define TESTING_EMBEDDER_TEST_MOCK_DELEGATE_H_
 
-#include "embedder_test.h"
+#include "testing/embedder_test.h"
 #include "testing/gmock/include/gmock/gmock.h"
 
 class EmbedderTestMockDelegate : public EmbedderTest::Delegate {
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:
diff --git a/testing/fx_string_testhelpers.cpp b/testing/fx_string_testhelpers.cpp
index 1ee705f..aebe1a8 100644
--- a/testing/fx_string_testhelpers.cpp
+++ b/testing/fx_string_testhelpers.cpp
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "fx_string_testhelpers.h"
+#include "testing/fx_string_testhelpers.h"
 
 #include <ios>
 #include <iomanip>