Refactor BlinkAXTreeSource::SerializeNode

The goal is to make it easier to read, and also easier to see which
attributes are being computed based on each accessibility mode.

Bug: none
Change-Id: Ic62a7db94d1e6383dabc1e5e0b7fa4ef78ce6e27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2220713
Commit-Queue: Dominic Mazzoni <dmazzoni@chromium.org>
Reviewed-by: Chris Hall <chrishall@chromium.org>
Cr-Commit-Position: refs/heads/master@{#773086}

content/renderer/accessibility/blink_ax_tree_source.h

@@ -131,6 +131,45 @@ class BlinkAXTreeSource
     return focus_;
   }
 
+  void SerializeBoundingBoxAttributes(blink::WebAXObject src,
+                                      AXContentNodeData* dst) const;
+  void SerializePDFAttributes(blink::WebAXObject src,
+                              AXContentNodeData* dst) const;
+  void SerializeSparseAttributes(blink::WebAXObject src,
+                                 AXContentNodeData* dst) const;
+  void SerializeNameAndDescriptionAttributes(blink::WebAXObject src,
+                                             AXContentNodeData* dst) const;
+  void SerializeValueAttributes(blink::WebAXObject src,
+                                AXContentNodeData* dst) const;
+  void SerializeStateAttributes(blink::WebAXObject src,
+                                AXContentNodeData* dst) const;
+  void SerializeStyleAttributes(blink::WebAXObject src,
+                                AXContentNodeData* dst) const;
+  void SerializeInlineTextBoxAttributes(blink::WebAXObject src,
+                                        AXContentNodeData* dst) const;
+  void SerializeMarkerAttributes(blink::WebAXObject src,
+                                 AXContentNodeData* dst) const;
+  void SerializeLiveRegionAttributes(blink::WebAXObject src,
+                                     AXContentNodeData* dst) const;
+  void SerializeListAttributes(blink::WebAXObject src,
+                               AXContentNodeData* dst) const;
+  void SerializeTableAttributes(blink::WebAXObject src,
+                                AXContentNodeData* dst) const;
+  void SerializeScrollAttributes(blink::WebAXObject src,
+                                 AXContentNodeData* dst) const;
+  void SerializeChooserPopupAttributes(blink::WebAXObject src,
+                                       AXContentNodeData* dst) const;
+  void SerializeOtherScreenReaderAttributes(blink::WebAXObject src,
+                                            AXContentNodeData* dst) const;
+  void SerializeEditableTextAttributes(blink::WebAXObject src,
+                                       AXContentNodeData* dst) const;
+  void SerializeElementAttributes(blink::WebAXObject src,
+                                  blink::WebElement element,
+                                  AXContentNodeData* dst) const;
+  void SerializeHTMLAttributes(blink::WebAXObject src,
+                               blink::WebElement element,
+                               AXContentNodeData* dst) const;
+
   blink::WebAXObject ComputeRoot() const;
 
   // Max length for attributes such as aria-label.