Add a feature flag to honor JavaScript content settings in PDFs

Add |chrome_pdf::features::kPdfHonorJsContentSettings| and the
corresponding UI in chrome://flags for enabling whether JavaScript
content settings get honored in PDFs.

The flag does not do anything yet.

Bug: 696650
Change-Id: Icaf97474617ad56ebc93c2e419e90b12c5385aed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2203480
Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
Reviewed-by: Tom Sepez <tsepez@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773482}

chrome/browser/about_flags.cc

@@ -3848,6 +3848,11 @@ const FeatureEntry kFeatureEntries[] = {
      flag_descriptions::kPdfFormSaveDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(chrome_pdf::features::kSaveEditedPDFForm)},
 
+    {"pdf-honor-js-content-settings",
+     flag_descriptions::kPdfHonorJsContentSettingsName,
+     flag_descriptions::kPdfHonorJsContentSettingsDescription, kOsDesktop,
+     FEATURE_VALUE_TYPE(chrome_pdf::features::kPdfHonorJsContentSettings)},
+
     {"pdf-two-up-view", flag_descriptions::kPdfTwoUpViewName,
      flag_descriptions::kPdfTwoUpViewDescription, kOsDesktop,
      FEATURE_VALUE_TYPE(chrome_pdf::features::kPDFTwoUpView)},

chrome/browser/flag-metadata.json

@@ -3547,6 +3547,11 @@
     "owners": [ "thestig" ],
     "expiry_milestone": 89
   },
+  {
+    "name": "pdf-honor-js-content-settings",
+    "owners": [ "dhoss", "tsepez" ],
+    "expiry_milestone": 90
+  },
   {
     "name": "pdf-two-up-view",
     "owners": ["nigi", "thestig"],

chrome/browser/flag_descriptions.cc

@@ -4089,6 +4089,12 @@ const char kPdfFormSaveName[] = "Save PDF Forms";
 const char kPdfFormSaveDescription[] =
     "Enable saving PDFs with filled form data.";
 
+const char kPdfHonorJsContentSettingsName[] =
+    "Honor JavaScript content settings in PDFs";
+const char kPdfHonorJsContentSettingsDescription[] =
+    "Enable whether an origin's JavaScript content settings are honored in "
+    "PDFs opened from that origin.";
+
 const char kPdfTwoUpViewName[] = "PDF Two-up View";
 const char kPdfTwoUpViewDescription[] =
     "Enable a new option to display two pages side by side in the PDF viewer.";

chrome/browser/flag_descriptions.h

@@ -2420,6 +2420,9 @@ extern const char kPdfAnnotationsDescription[];
 extern const char kPdfFormSaveName[];
 extern const char kPdfFormSaveDescription[];
 
+extern const char kPdfHonorJsContentSettingsName[];
+extern const char kPdfHonorJsContentSettingsDescription[];
+
 extern const char kPdfTwoUpViewName[];
 extern const char kPdfTwoUpViewDescription[];
 

pdf/pdf_features.cc

@@ -21,6 +21,9 @@ const base::Feature kPDFAnnotations = {"PDFAnnotations",
 #endif  // defined(OS_CHROMEOS)
 };
 
+const base::Feature kPdfHonorJsContentSettings = {
+    "PdfHonorJsContentSettings", base::FEATURE_DISABLED_BY_DEFAULT};
+
 const base::Feature kPDFTwoUpView = {"PDFTwoUpView",
                                      base::FEATURE_DISABLED_BY_DEFAULT};
 

pdf/pdf_features.h

@@ -16,6 +16,7 @@ namespace features {
 extern const base::Feature kAccessiblePDFForm;
 extern const base::Feature kAccessiblePDFHighlight;
 extern const base::Feature kPDFAnnotations;
+extern const base::Feature kPdfHonorJsContentSettings;
 extern const base::Feature kPDFTwoUpView;
 extern const base::Feature kPDFViewerUpdate;
 extern const base::Feature kSaveEditedPDFForm;

tools/metrics/histograms/enums.xml

@@ -41462,6 +41462,7 @@ from previous Chrome versions.
   <int value="1192913630" label="OfflinePagesBackgroundLoading:disabled"/>
   <int value="1193385506" label="OmniboxLooseMaxLimitOnDedicatedRows:enabled"/>
   <int value="1194496204" label="NewWallpaperPicker:enabled"/>
+  <int value="1194896796" label="PdfHonorJsContentSettings:disabled"/>
   <int value="1195087468" label="ProminentDarkModeActiveTabTitle:enabled"/>
   <int value="1196644408" label="performance-monitor-gathering"/>
   <int value="1196834473" label="disable-smart-virtual-keyboard"/>
@@ -41768,6 +41769,7 @@ from previous Chrome versions.
   <int value="1529979182" label="EnablePasswordSelection:enabled"/>
   <int value="1530113113" label="disable-pushstate-throttle"/>
   <int value="1530177325" label="LanguagesPreference:disabled"/>
+  <int value="1530182188" label="PdfHonorJsContentSettings:enabled"/>
   <int value="1531164533" label="SyncPseudoUSSFavicons:disabled"/>
   <int value="1531741496" label="DragFromShelfToHomeOrOverview:disabled"/>
   <int value="1534222388" label="EnableEphemeralFlashPermission:enabled"/>