Revert of Remove some dead PDF code. (patchset #3 id:40001 of https://codereview.chromium.org/1552833003/ )

Reason for revert:
Causes a crash.

BUG=574440

Original issue's description:
> Remove some dead PDF code.
>
> Committed: https://crrev.com/e2cb8a125d8079f85c16290ee761460cf54b9ec4
> Cr-Commit-Position: refs/heads/master@{#367398}

TBR=raymes@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1557423002

Cr-Commit-Position: refs/heads/master@{#367570}

3 files changed, 50 insertions, 3 deletions

diff --git a/pdf/pdf_engine.h b/pdf/pdf_engine.h
index c5d33c8..7df4bff2 100644
--- a/pdf/pdf_engine.h
+++ b/pdf/pdf_engine.h
@@ -222,6 +222,7 @@ class PDFEngine {
   virtual void RotateCounterclockwise() = 0;
   virtual std::string GetSelectedText() = 0;
   virtual std::string GetLinkAtPosition(const pp::Point& point) = 0;
+  virtual bool IsSelecting() = 0;
   // Checks the permissions associated with this document.
   virtual bool HasPermission(DocumentPermission permission) const = 0;
   virtual void SelectAll() = 0;
@@ -229,6 +230,8 @@ class PDFEngine {
   virtual int GetNumberOfPages() = 0;
   // Gets the 0-based page number of |destination|, or -1 if it does not exist.
   virtual int GetNamedDestinationPage(const std::string& destination) = 0;
+  // Gets the index of the first visible page, or -1 if none are visible.
+  virtual int GetFirstVisiblePage() = 0;
   // Gets the index of the most visible page, or -1 if none are visible.
   virtual int GetMostVisiblePage() = 0;
   // Gets the rectangle of the page including shadow.
@@ -241,6 +244,8 @@ class PDFEngine {
   // Gets the offset of the vertical scrollbar from the top in document
   // coordinates.
   virtual int GetVerticalScrollbarYPosition() = 0;
+  // Paints page thumbnail to the ImageData.
+  virtual void PaintThumbnail(pp::ImageData* image_data, int index) = 0;
   // Set color / grayscale rendering modes.
   virtual void SetGrayscale(bool grayscale) = 0;
   // Callback for timer that's set with ScheduleCallback().
diff --git a/pdf/pdfium/pdfium_engine.cc b/pdf/pdfium/pdfium_engine.cc
index 87c7dcc..83291bc 100644
--- a/pdf/pdfium/pdfium_engine.cc
+++ b/pdf/pdfium/pdfium_engine.cc
@@ -534,6 +534,7 @@ PDFiumEngine::PDFiumEngine(PDFEngine::Client* client)
       fpdf_availability_(NULL),
       next_timer_id_(0),
       last_page_mouse_down_(-1),
+      first_visible_page_(-1),
       most_visible_page_(-1),
       called_do_document_action_(false),
       render_grayscale_(false),
@@ -2266,6 +2267,10 @@ std::string PDFiumEngine::GetLinkAtPosition(const pp::Point& point) {
   return url;
 }
 
+bool PDFiumEngine::IsSelecting() {
+  return selecting_;
+}
+
 bool PDFiumEngine::HasPermission(DocumentPermission permission) const {
   // PDF 1.7 spec, section 3.5.2 says: "If the revision number is 2 or greater,
   // the operations to which user access can be controlled are as follows: ..."
@@ -2334,6 +2339,11 @@ int PDFiumEngine::GetNamedDestinationPage(const std::string& destination) {
   return dest ? FPDFDest_GetPageIndex(doc_, dest) : -1;
 }
 
+int PDFiumEngine::GetFirstVisiblePage() {
+  CalculateVisiblePages();
+  return first_visible_page_;
+}
+
 int PDFiumEngine::GetMostVisiblePage() {
   CalculateVisiblePages();
   return most_visible_page_;
@@ -2350,6 +2360,26 @@ pp::Rect PDFiumEngine::GetPageContentsRect(int index) {
   return GetScreenRect(pages_[index]->rect());
 }
 
+void PDFiumEngine::PaintThumbnail(pp::ImageData* image_data, int index) {
+  FPDF_BITMAP bitmap = FPDFBitmap_CreateEx(
+      image_data->size().width(), image_data->size().height(),
+      FPDFBitmap_BGRx, image_data->data(), image_data->stride());
+
+  if (pages_[index]->available()) {
+    FPDFBitmap_FillRect(bitmap, 0, 0, image_data->size().width(),
+                        image_data->size().height(), 0xFFFFFFFF);
+
+    FPDF_RenderPageBitmap(
+        bitmap, pages_[index]->GetPage(), 0, 0, image_data->size().width(),
+        image_data->size().height(), 0, GetRenderingFlags());
+  } else {
+    FPDFBitmap_FillRect(bitmap, 0, 0, image_data->size().width(),
+                        image_data->size().height(), kPendingPageColor);
+  }
+
+  FPDFBitmap_Destroy(bitmap);
+}
+
 void PDFiumEngine::SetGrayscale(bool grayscale) {
   render_grayscale_ = grayscale;
 }
@@ -2678,10 +2708,15 @@ void PDFiumEngine::CalculateVisiblePages() {
   // screen coordinates.
   form_highlights_.clear();
 
-  int most_visible_page = visible_pages_.empty() ? 0 : visible_pages_.front();
-  DCHECK_GE(most_visible_page, 0);
+  if (visible_pages_.size() == 0)
+    first_visible_page_ = -1;
+  else
+    first_visible_page_ = visible_pages_.front();
+
+  int most_visible_page = first_visible_page_;
   // Check if the next page is more visible than the first one.
-  if (!pages_.empty() &&
+  if (most_visible_page != -1 &&
+      pages_.size() > 0 &&
       most_visible_page < static_cast<int>(pages_.size()) - 1) {
     pp::Rect rc_first =
         visible_rect.Intersect(GetPageScreenRect(most_visible_page));
diff --git a/pdf/pdfium/pdfium_engine.h b/pdf/pdfium/pdfium_engine.h
index e0b8af5..88a2575 100644
--- a/pdf/pdfium/pdfium_engine.h
+++ b/pdf/pdfium/pdfium_engine.h
@@ -77,16 +77,19 @@ class PDFiumEngine : public PDFEngine,
   void RotateCounterclockwise() override;
   std::string GetSelectedText() override;
   std::string GetLinkAtPosition(const pp::Point& point) override;
+  bool IsSelecting() override;
   bool HasPermission(DocumentPermission permission) const override;
   void SelectAll() override;
   int GetNumberOfPages() override;
   pp::VarArray GetBookmarks() override;
   int GetNamedDestinationPage(const std::string& destination) override;
+  int GetFirstVisiblePage() override;
   int GetMostVisiblePage() override;
   pp::Rect GetPageRect(int index) override;
   pp::Rect GetPageContentsRect(int index) override;
   pp::Rect GetPageScreenRect(int page_index) const override;
   int GetVerticalScrollbarYPosition() override { return position_.y(); }
+  void PaintThumbnail(pp::ImageData* image_data, int index) override;
   void SetGrayscale(bool grayscale) override;
   void OnCallback(int id) override;
   std::string GetPageAsJSON(int index) override;
@@ -667,6 +670,10 @@ class PDFiumEngine : public PDFEngine,
   // Holds the page index of the last page that the mouse clicked on.
   int last_page_mouse_down_;
 
+  // Holds the page index of the first visible page; refreshed by calling
+  // CalculateVisiblePages()
+  int first_visible_page_;
+
   // Holds the page index of the most visible page; refreshed by calling
   // CalculateVisiblePages()
   int most_visible_page_;