[unseasoned-pdf] Avoid using blink::WebString in the Pepper process

blink::WebString's allocators can only be used if Blink is initialized.
Instead of initializing Blink, just avoid using blink::WebString in the
few places they're used in the Pepper process, at least for as long as
the Pepper process exists.

Change-Id: I73130fb840179a2c02e6ed6e1aeffae2e4f2f704
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3018059
Commit-Queue: Daniel Hosseinian <dhoss@chromium.org>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#900584}

pdf/pdfium/pdfium_font_linux.cc

@@ -144,7 +144,12 @@ void* MapFont(FPDF_SYSFONTINFO*,
   if (strcmp(face, "Symbol") == 0)
     return nullptr;
 
+  // TODO(crbug.com/702993): `blink::WebFontDescription::family` is a
+  // `blink::WebString`, which can only be used if Blink is initialized. Store
+  // the field in `font_family` for now, but remove the variable when this code
+  // will only execute in a renderer process.
   blink::WebFontDescription desc;
+  std::string font_family;
 
   if (pitch_family & FXFONT_FF_FIXEDPITCH) {
     desc.generic_family = blink::WebFontDescription::kGenericFamilyMonospace;
@@ -203,7 +208,7 @@ void* MapFont(FPDF_SYSFONTINFO*,
   size_t i;
   for (i = 0; i < base::size(kPdfFontSubstitutions); ++i) {
     if (strcmp(face, kPdfFontSubstitutions[i].pdf_name) == 0) {
-      desc.family = blink::WebString::FromUTF8(kPdfFontSubstitutions[i].face);
+      font_family = kPdfFontSubstitutions[i].face;
       if (kPdfFontSubstitutions[i].bold)
         desc.weight = blink::WebFontDescription::kWeightBold;
       if (kPdfFontSubstitutions[i].italic)
@@ -228,15 +233,16 @@ void* MapFont(FPDF_SYSFONTINFO*,
     if (face_utf8.empty())
       return nullptr;
 
-    desc.family = blink::WebString::FromUTF8(face_utf8);
+    font_family = face_utf8;
     desc.weight = WeightToBlinkWeight(weight);
     desc.italic = italic > 0;
   }
 
   if (PDFiumEngine::GetFontMappingMode() == FontMappingMode::kPepper)
-    return MapPepperFont(desc, charset);
+    return MapPepperFont(desc, font_family, charset);
 
   DCHECK_EQ(PDFiumEngine::GetFontMappingMode(), FontMappingMode::kBlink);
+  desc.family = blink::WebString::FromUTF8(font_family);
   return GetBlinkFontMapper().MapFont(desc, charset);
 }
 

pdf/ppapi_migration/pdfium_font_linux.cc

@@ -39,8 +39,11 @@ FONT_WEIGHT_MATCH_ASSERT(900);
 
 }  // namespace
 
-void* MapPepperFont(const blink::WebFontDescription& desc, int charset) {
+void* MapPepperFont(const blink::WebFontDescription& desc,
+                    const std::string& font_family,
+                    int charset) {
   DCHECK(pp::PDF::IsAvailable());
+  DCHECK(desc.family.IsEmpty());
 
   pp::BrowserFontDescription description;
 
@@ -52,7 +55,7 @@ void* MapPepperFont(const blink::WebFontDescription& desc, int charset) {
     description.set_family(PP_BROWSERFONT_TRUSTED_FAMILY_SERIF);
   }
 
-  description.set_face(desc.family.Utf8());
+  description.set_face(font_family);
   description.set_weight(ToPepperWeight(desc.weight));
   description.set_italic(desc.italic);
 

pdf/ppapi_migration/pdfium_font_linux.h

@@ -5,6 +5,8 @@
 #ifndef PDF_PPAPI_MIGRATION_PDFIUM_FONT_LINUX_H_
 #define PDF_PPAPI_MIGRATION_PDFIUM_FONT_LINUX_H_
 
+#include <string>
+
 namespace blink {
 struct WebFontDescription;
 }
@@ -15,9 +17,12 @@ class Instance;
 
 namespace chrome_pdf {
 
-// Returns a handle to the font mapped based on `desc` and `charset`, for use
+// Returns a handle to the font mapped based on `desc`, `font_family`, and
-// as the font_id in GetPepperFontData() and DeletePepperFont() below.
+// `charset`. The handle is for use as the `font_id` in `GetPepperFontData()`
-void* MapPepperFont(const blink::WebFontDescription& desc, int charset);
+// and `DeletePepperFont()` below.
+void* MapPepperFont(const blink::WebFontDescription& desc,
+                    const std::string& font_family,
+                    int charset);
 
 // Reads data from the `font_id` handle for `table` into a `buffer` of
 // `buf_size`. Returns the amount of data read on success, or 0 on failure. If