Bump LOK and fix handling full document invalidation events

src/electron/DEPS

@@ -11,7 +11,7 @@ vars = {
     '0e5d146ba13101a1302d59ea6e6e0b3cace4ae38',
 
   'pyyaml_version': '3.12',
-  'libreofficekit_version': 'v0.4.11',
+  'libreofficekit_version': 'v0.5.2',
 
   'chromium_git': 'https://chromium.googlesource.com',
   'electron_git': 'https://github.com/electron',

src/electron/ELECTRON_VERSION

@@ -1 +1 @@
-20.3.0-beta1
+20.3.0-beta2

src/electron/office/office_web_plugin.cc

@@ -557,8 +557,15 @@ void OfficeWebPlugin::HandleInvalidateTiles(std::string payload) {
 
   // TODO: handle non-text document types for parts
   if (payload_sv == "EMPTY") {
-    ScheduleAvailableAreaPaint();
-  } else {
+    base::TimeTicks now = base::TimeTicks::Now();
+    if (last_full_invalidation_time_.is_null() || (now - last_full_invalidation_time_) > base::Milliseconds(10)) {
+      ScheduleAvailableAreaPaint();
+      last_full_invalidation_time_ = now;
+    }
+   // weirdly, LOK seems to be issuing a full tile invalidation FOR EVERY PAGE, then the whole document
+   // skip those page invalidations which are of the form "EMPTY, #, #"
+   // rendering was getting N+1 full document re-renders where N=number of pages, that's bad
+  } else if (payload_sv.substr(0, 5) != "EMPTY") {
     std::string_view::const_iterator start = payload_sv.begin();
     gfx::Rect dirty_rect =
         office::lok_callback::ParseRect(start, payload_sv.end());

src/electron/office/office_web_plugin.h

@@ -16,6 +16,7 @@
 #include <vector>
 #include "base/memory/scoped_refptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/time/time.h"
 #include "cc/paint/paint_image.h"
 #include "gin/handle.h"
 #include "include/core/SkImage.h"
@@ -268,6 +269,7 @@ class OfficeWebPlugin : public blink::WebPlugin,
 
   scoped_refptr<base::SequencedTaskRunner> task_runner_;
   office::CancelFlagPtr paint_cancel_flag_;
+  base::TimeTicks last_full_invalidation_time_ = base::TimeTicks();
 
   v8::Global<v8::ObjectTemplate> v8_template_;
   v8::Global<v8::Object> v8_object_;