[wayland] Use pending maximize mode in decoration updates

Summary:
The change to make maximize mode asynchronous featured the comment

>Things are a bit complex with borders. Technically we
>shouldn't update them till we get a response, but we also need to have
>the correct geometry of the full size window in our request. For now
>they behave as before, updating when we request the change.

We call setNoBorder when we request the geometry but decoratedClient
also checks the maximise mode, in order to follow the scheme above we
need this to operate on the requested state not current state.

X is unaffected.

This fixes the borders being restored correct after maximize/restore.

Test Plan:
Chose a theme with visible borders
Maximised a window and back
They restored

Reviewers: #kwin, zzag

Reviewed By: #kwin, zzag

Subscribers: zzag, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D15991

abstract_client.cpp

@@ -204,6 +204,11 @@ bool AbstractClient::isCurrentTab() const
     return !tab_group || tab_group->current() == this;
 }
 
+MaximizeMode AbstractClient::requestedMaximizeMode() const
+{
+    return maximizeMode();
+}
+
 xcb_timestamp_t AbstractClient::userTime() const
 {
     return XCB_TIME_CURRENT_TIME;

abstract_client.h

@@ -456,7 +456,16 @@ public:
     */
     bool isCurrentTab() const;
     virtual QRect geometryRestore() const = 0;
+    /**
+     * The currently applied maximize mode
+     */
     virtual MaximizeMode maximizeMode() const = 0;
+    /**
+     * The maximise mode requested by the server.
+     * For X this always matches maximizeMode, for wayland clients it
+     * is asyncronous
+     */
+    virtual MaximizeMode requestedMaximizeMode() const;
     void maximize(MaximizeMode);
     void setMaximize(bool vertically, bool horizontally);
     virtual bool noBorder() const = 0;

decorations/decoratedclient.cpp

@@ -271,7 +271,7 @@ int DecoratedClientImpl::height() const
 
 bool DecoratedClientImpl::isMaximizedVertically() const
 {
-    return m_client->maximizeMode() & MaximizeVertical;
+    return m_client->requestedMaximizeMode() & MaximizeVertical;
 }
 
 bool DecoratedClientImpl::isMaximized() const
@@ -281,7 +281,7 @@ bool DecoratedClientImpl::isMaximized() const
 
 bool DecoratedClientImpl::isMaximizedHorizontally() const
 {
-    return m_client->maximizeMode() & MaximizeHorizontal;
+    return m_client->requestedMaximizeMode() & MaximizeHorizontal;
 }
 
 Qt::Edges DecoratedClientImpl::adjacentScreenEdges() const

shell_client.cpp

@@ -914,6 +914,11 @@ MaximizeMode ShellClient::maximizeMode() const
     return m_maximizeMode;
 }
 
+MaximizeMode ShellClient::requestedMaximizeMode() const
+{
+    return m_requestedMaximizeMode;
+}
+
 bool ShellClient::noBorder() const
 {
     if (isInternal()) {

shell_client.h

@@ -95,6 +95,8 @@ public:
     }
     void hideClient(bool hide) override;
     MaximizeMode maximizeMode() const override;
+    MaximizeMode requestedMaximizeMode() const override;
+
     QRect geometryRestore() const override {
         return m_geomMaximizeRestore;
     }