Print Preview: Add option to rasterize PDFs and add JPEG compression.

Add checkbox to print preview to select rasterized PDF output. When
selected, PDF will be rasterized and printed as a series of images.
Images will be JPEG encoded.

Preliminary design doc: https://docs.google.com/a/google.com/document/d/1UTzurMuPeRgx2PcnTMuAq5iM5_R2QBNGp-9lzgtwT2k/edit?usp=sharing

Depends on http://crrev.com/2529543003

Linked to launch bug, should also resolve 534945,550205,480628

BUG=675798
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:closure_compilation

Review-Url: https://codereview.chromium.org/2524143003
Cr-Commit-Position: refs/heads/master@{#440897}
diff --git a/chrome/browser/about_flags.cc b/chrome/browser/about_flags.cc
index 4afb92b..dada3f3 100644
--- a/chrome/browser/about_flags.cc
+++ b/chrome/browser/about_flags.cc
@@ -2074,6 +2074,9 @@
          features::kDisplayPersistenceToggleInPermissionPrompts)},
 #endif
 #if BUILDFLAG(ENABLE_PRINT_PREVIEW)
+    {"print-pdf-as-image", IDS_FLAGS_PRINT_PDF_AS_IMAGE_NAME,
+      IDS_FLAGS_PRINT_PDF_AS_IMAGE_DESCRIPTION, kOsDesktop,
+      FEATURE_VALUE_TYPE(features::kPrintPdfAsImage)},
     {"print-scaling", IDS_FLAGS_PRINT_SCALING_NAME,
      IDS_FLAGS_PRINT_SCALING_DESCRIPTION, kOsDesktop,
      FEATURE_VALUE_TYPE(features::kPrintScaling)},