Printing: Load the source PDF only once.

pdf/pdf.h

Index: pdf/pdf.h
diff --git a/pdf/pdf.h b/pdf/pdf.h
index fa3ae590aba83e861999da7f82a0dbc65afcbaf4..2c0112454216c10476cedfcf88099ab01944267c 100644
--- a/pdf/pdf.h
+++ b/pdf/pdf.h
@@ -36,9 +36,7 @@ void PPP_ShutdownModule();
 const void* PPP_GetInterface(const char* interface_name);
 
 #if defined(OS_WIN)
-// |pdf_buffer| is the buffer that contains the entire PDF document to be
-//     rendered.
-// |buffer_size| is the size of |pdf_buffer| in bytes.
+// |pdf_handle| is the handle to the PDF document.
 // |page_number| is the 0-based index of the page to be rendered.
 // |dc| is the device context to render into.
 // |dpi| and |dpi_y| is the resolution. If the value is -1, the dpi from the DC
@@ -63,8 +61,7 @@ const void* PPP_GetInterface(const char* interface_name);
 // |autorotate| specifies whether the final image should be rotated to match
 //     the output bound.
 // Returns false if the document or the page number are not valid.
-bool RenderPDFPageToDC(const void* pdf_buffer,
-                       int buffer_size,
+bool RenderPDFPageToDC(void* pdf_handle,
                        int page_number,
                        HDC dc,
                        int dpi,
@@ -84,29 +81,35 @@ void SetPDFEnsureTypefaceCharactersAccessible(
 void SetPDFUseGDIPrinting(bool enable);
 #endif  // defined(OS_WIN)
 
-// |page_count| and |max_page_width| are optional and can be NULL.
+// All the out parameters are optional and can be NULL.
 // Returns false if the document is not valid.
+// Returns true on success. In which case, if |pdf_handle| is not NULL, then
+// the handle is guaranteed to be valid and not NULL. The caller takes
+// ownership of |pdf_handle| and must call ReleasePDFHandle() on it when done.
 bool GetPDFDocInfo(const void* pdf_buffer,
-                   int buffer_size, int* page_count,
-                   double* max_page_width);
+                   int buffer_size,
+                   int* page_count,
+                   double* max_page_width,
+                   void** pdf_handle);
+
+// Releases the handle received from GetPDFDocInfo().
+// |pdf_handle| can be NULL.
+void ReleasePDFHandle(void* pdf_handle);
 
 // Gets the dimensions of a specific page in a document.
-// |pdf_buffer| is the buffer that contains the entire PDF document to be
-//     rendered.
-// |pdf_buffer_size| is the size of |pdf_buffer| in bytes.
+// |pdf_handle| is the handle to the PDF document.
 // |page_number| is the page number that the function will get the dimensions
 //     of.
 // |width| is the output for the width of the page in points.
 // |height| is the output for the height of the page in points.
 // Returns false if the document or the page number are not valid.
-bool GetPDFPageSizeByIndex(const void* pdf_buffer,
-                           int pdf_buffer_size, int page_number,
-                           double* width, double* height);
+bool GetPDFPageSizeByIndex(void* pdf_handle,
+                           int page_number,
+                           double* width,
+                           double* height);
 
 // Renders PDF page into 4-byte per pixel BGRA color bitmap.
-// |pdf_buffer| is the buffer that contains the entire PDF document to be
-//     rendered.
-// |pdf_buffer_size| is the size of |pdf_buffer| in bytes.
+// |pdf_handle| is the handle to the PDF document.
 // |page_number| is the 0-based index of the page to be rendered.
 // |bitmap_buffer| is the output buffer for bitmap.
 // |bitmap_width| is the width of the output bitmap.
@@ -115,8 +118,7 @@ bool GetPDFPageSizeByIndex(const void* pdf_buffer,
 // |autorotate| specifies whether the final image should be rotated to match
 //     the output bound.
 // Returns false if the document or the page number are not valid.
-bool RenderPDFPageToBitmap(const void* pdf_buffer,
-                           int pdf_buffer_size,
+bool RenderPDFPageToBitmap(void* pdf_handle,
                            int page_number,
                            void* bitmap_buffer,
                            int bitmap_width,