Better expose PDFiumEngine::plugin_size() callers that fail DCHECK

Use DUMP_WILL_BE_NOTREACHED() in PDFiumEngine::plugin_size() instead of
a DCHECK(), so that the DCHECK() failures consistently generate
non-fatal dumped in all builds. Temporarily un-inline plugin_size() to
avoid putting more code into the header.

Bug: 40193305
Change-Id: I92459e6d36fe33d296404486dd4b93615113a719
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5618930
Commit-Queue: Lei Zhang <thestig@chromium.org>
Reviewed-by: Alan Screen <awscreen@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313170}

pdf/pdfium/pdfium_engine.cc

@@ -2719,6 +2719,15 @@ void PDFiumEngine::AppendBlankPages(size_t num_pages) {
   LoadPageInfo();
 }
 
+gfx::Size PDFiumEngine::plugin_size() const {
+  if (plugin_size_.has_value()) {
+    return plugin_size_.value();
+  }
+  // TODO(crbug.com/40193305): Fix call sites and inline this getter again.
+  DUMP_WILL_BE_NOTREACHED();
+  return gfx::Size();
+}
+
 void PDFiumEngine::LoadDocument() {
   // Check if the document is ready for loading. If it isn't just bail for now,
   // we will call LoadDocument() again later.

pdf/pdfium/pdfium_engine.h

@@ -14,7 +14,6 @@
 #include <string>
 #include <vector>
 
-#include "base/check.h"
 #include "base/containers/flat_map.h"
 #include "base/containers/span.h"
 #include "base/memory/raw_ptr.h"
@@ -279,11 +278,7 @@ class PDFiumEngine : public PDFEngine,
   friend class PDFiumTestBase;
   friend class SelectionChangeInvalidator;
 
-  gfx::Size plugin_size() const {
-    // TODO(crbug.com/40193305): Just use .value() after fixing call sites.
-    DCHECK(plugin_size_.has_value());
-    return plugin_size_.value_or(gfx::Size());
-  }
+  gfx::Size plugin_size() const;
 
   // We finished getting the pdf file, so load it. This will complete
   // asynchronously (due to password fetching) and may be run multiple times.