[geary/wip/conversation-polish] Rework sending ClientWebView sending preferred height from JS, again

[Michael Gratton <mjog src gnome org>]

commit 64a8d571acee78c68cd08ac463327f05d343e83d
Author: Michael Gratton <mike vee net>
Date:   Thu Jan 31 09:46:43 2019 +1100

    Rework sending ClientWebView sending preferred height from JS, again
    
    Don't allow any preferred heigh updates to be sent until DOM has been
    fully loaded and manupliated (in particular by ConversaionWebView) so
    it is vaugely correct when first resized and takes a collapsed quote
    heights into account.

 ui/client-web-view.js | 35 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 18 deletions(-)
---
diff --git a/ui/client-web-view.js b/ui/client-web-view.js
index 810e62eb..ac2abe9e 100644
--- a/ui/client-web-view.js
+++ b/ui/client-web-view.js
@@ -36,6 +36,10 @@ PageState.prototype = {
             }
         });
 
+        document.addEventListener("DOMContentLoaded", function(e) {
+            state.loaded();
+        });
+
         // Coalesce multiple calls to updatePreferredHeight using a
         // timeout to avoid the overhead of multiple JS messages sent
         // to the app and hence view multiple resizes being queued.
@@ -45,23 +49,10 @@ PageState.prototype = {
                 clearTimeout(queueTimeout);
             }
             queueTimeout = setTimeout(
-                function() { state.updatePreferredHeight(); }, 10
+                function() { state.updatePreferredHeight(); }, 100
             );
         };
 
-        // Queues an update after the DOM has been initially loaded
-        // and had any changes made to it by derived classes.
-        document.addEventListener("DOMContentLoaded", function(e) {
-            // Always fire a prefered height update first so that it
-            // will be vaguegly correct when notifying of the HTML
-            // load completing.
-            state.updatePreferredHeight();
-            state.loaded();
-            // Still need to queue an update though since it still may
-            // be updated after this event has been fired.
-            queuePreferredHeightUpdate();
-        });
-
         // Queues an update when the complete document is loaded.
         //
         // Note also that the delay introduced here by this last call
@@ -92,13 +83,17 @@ PageState.prototype = {
         }, false); // load does not bubble
     },
     getPreferredHeight: function() {
-        return window.document.documentElement.scrollHeight;
+        return window.document.body.scrollHeight;
     },
     getHtml: function() {
         return document.body.innerHTML;
     },
     loaded: function() {
         this.isLoaded = true;
+        // Always fire a prefered height update first so that it will
+        // be vaguegly correct when notifying of the HTML load
+        // completing.
+        this.updatePreferredHeight();
         window.webkit.messageHandlers.contentLoaded.postMessage(null);
     },
     loadRemoteImages: function() {
@@ -145,15 +140,19 @@ PageState.prototype = {
             height = this.getPreferredHeight();
         }
 
-        let updated = false;
-        if (height > 0 && height != this.lastPreferredHeight) {
+        // Don't send the message until after the DOM has been fully
+        // loaded and processed by any derived classes. Since
+        // ConversationPageState may collapse any quotes, sending the
+        // current preferred height before then may send a value that
+        // is too large, causing the message body view to grow then
+        // shrink again, leading to visual flicker.
+        if (this.isLoaded && height > 0 && height != this.lastPreferredHeight) {
             updated = true;
             this.lastPreferredHeight = height;
             window.webkit.messageHandlers.preferredHeightChanged.postMessage(
                 height
             );
         }
-        return updated;
     },
     checkCommandStack: function() {
         let canUndo = document.queryCommandEnabled("undo");