[problems] Implemented clear-all in problems view.

Fixes: #7979

Added a `Clear-All` toolbar item, which clears all the existing problem
markers

Signed-off-by: Anas Shahid <muhammad.shahid@ericsson.com>

packages/markers/src/browser/problem/problem-contribution.ts

@@ -49,6 +49,13 @@ export namespace ProblemsCommands {
     export const COPY_MESSAGE: Command = {
         id: 'problems.copy.message',
     };
+    export const CLEAR_ALL: Command = {
+        id: 'problems.clear.all'
+    };
+    export const CLEAR_ALL_TOOLBAR: Command = {
+        id: 'problems.clear.all.toolbar',
+        iconClass: 'theia-remove-all-icon'
+    };
 }
 
 @injectable()
@@ -145,6 +152,14 @@ export class ProblemContribution extends AbstractViewContribution<ProblemWidget>
                 execute: selection => this.copyMessage(selection)
             })
         );
+        commands.registerCommand(ProblemsCommands.CLEAR_ALL, {
+            execute: () => this.clearAllMarkers()
+        });
+        commands.registerCommand(ProblemsCommands.CLEAR_ALL_TOOLBAR, {
+            isEnabled: widget => this.withWidget(widget, () => true),
+            isVisible: widget => this.withWidget(widget, () => true),
+            execute: () => this.clearAllMarkers()
+        });
     }
 
     registerMenus(menus: MenuModelRegistry): void {
@@ -173,6 +188,12 @@ export class ProblemContribution extends AbstractViewContribution<ProblemWidget>
             tooltip: 'Collapse All',
             priority: 0,
         });
+        toolbarRegistry.registerItem({
+            id: ProblemsCommands.CLEAR_ALL_TOOLBAR.id,
+            command: ProblemsCommands.CLEAR_ALL_TOOLBAR.id,
+            tooltip: 'Clear All',
+            priority: 1,
+        });
     }
 
     protected async collapseAllProblems(): Promise<void> {
@@ -185,6 +206,13 @@ export class ProblemContribution extends AbstractViewContribution<ProblemWidget>
         }
     }
 
+    /**
+     * Clears all the markers in the problem channel.
+     */
+    protected clearAllMarkers(): void {
+        this.problemManager.cleanAllMarkers();
+    }
+
     protected addToClipboard(content: string): void {
         const handleCopy = (e: ClipboardEvent) => {
             document.removeEventListener('copy', handleCopy);